Thanks for the shout out! I'm glad my answers have been helpful. let's dive into your questions:

How important was it? If not, why is that view so common? Is that number excluding people who weren't members of a church but still attended occasionally?

Like today, I'd say the idea of "how important" is rather relative. Jon Butler (and other historians of this period) have aimed to come up with numbers that we can get from sources. We can get estimates of about 15% by examining the churches in cities and towns, adding up the number of people (usually by families) and subtract it from the total number of people who lived in a town or city. This enables us to know who was going to churches and how often.

It also depends on what denomination of Christianity you're discussing as well. For instance, the catholic church could not own physical property in Maryland until after the start of the American Revolution. As a result, Catholics (probably about 7% of the population in Maryland was Catholic by this point) could not attend a church. Certain wealthy Catholics in the state, such as Charles Carroll of Carlton and his father hosted mass in their home, but again, this was more informal.

On the flip side, in the same state, Quakers were much more religiously adherent. Out of about 150,000 free white people in Maryland around 1776, only 3,000 people were Quakers. However, of these 3,000, they were highly involved in their local meetings (Quakers do not refer to their congregations as churches, and instead refer to them as meetings). Records indicate that Most Quakers attended their Sunday meeting with regularity, usually every week, with a high number of Quakers (usually those who lives in towns like Baltimore or cities like Annapolis) also attending a mid-week meeting on Wednesdays or Thursdays.

But 65% of Maryland were Anglicans, and most Anglicans took their faith (generally speaking) much less formally. Part of this is that 95% of America's population lived rurally and it usually would be too far to attend a church service on Sunday, especially since churches were not as common as they would become in the 19th century. [1,2]

People still participated in what I would call minor religious functions. Chaplains and ministers usually prayed before meetings of Assemblies. People who didn't attend church regularly still got married in churches. People likely still prayed. Children who were fortunate enough to attend schools were often taught to read the bible. But as far as if these beliefs impacted their daily life, that's a matter of debate.

How many people regularly attended church in this period vs. only attending occasionally or for holidays?

This is something that is much harder to quantify. The historian you reference, Patricia Bonomi, has numbers that include people who regularly attended church services, but were not full members. Again, it's just hard to know for certain because most 18th century church records focus on members and not just folks who popped in from time to time.

Was religious participation higher in cities with easy access to a church? In other words, is the low attendance driven merely by the scarcity of churches and the difficulty of reaching a church for people who lived scattered on farms?

This is likely at least part of the case. We know that the number of churches and ministers exploded in the early 19th century, and this enabled people who didn't have access to churches to get there with more relative ease. Cities were also tiny, with only 3 cities by 1776 that had populations over 15,0000 people (out of a population of 2.5 million)

I assume that most colonists would still identify as Christians even if they don't attend church, but what do we know about how many people would call themselves Christians, and what there beliefs were?

Scholars of this period would generally agree that if you define "being a Christian" as a person's affirmation that "Jesus of Nazareth was divine, died and was resurrected and that people need to believe in him to have access to heaven," than the overwhelming majority, probably in the 99th percentile or more would say "yes." But other elements that we typically wouldn't define as having anything to do with Christianity, like magic and the occult were also other things that influenced people during this period. The article by Butler “Magic, Astrology, and the Early American Religious Heritage, 1600-1760” goes into this, in detail.

Was atheism, or general deism common?

Not very common and it appears to be mostly found amongst the well-educated and the elite.

How did this compare to other majority Christian nations at the time, particularly England and its colonies?

I honestly haven't studied Christianity in Great Britain as much as I would like, so I'm going to hold off on answering this question since I wouldn't be able to provide a source if asked.

• Were there major differences in religious belief between upper class Americans and the average person of the time? I know Thomas Jefferson and some other other founders had unorthodox views on Christianity.

This is hard to answer since it requires that I rely on generalities. Instead, I'll use a specific figure that can help me discuss it instead. George Washington was a man who was remembered as being pious, but closer examination into his life reveals a man who was very indifferent towards religion in general. If you search his personal writings (letters, journals, etc.), you'll see that he only references Christianity or Jesus on a handful of occasions and that Christian beliefs did not greatly impact his life or decision making one way or another. However, when he was around people, especially as Commander-in-Chief of the Continental Army, he attended church services whenever he could. As his biographer Ron Chernow wrote:

Many mysteries have surrounded George Washington's religious beliefs. A pair of notable acquaintances raised questions about his faith. Thomas Jefferson once remarked cynically that Washington "has divines minister constantly about him because he thinks it right to keep up appearances but is an unbeliever." Jefferson contended that when Washington stepped down as president, a group of clergy-men presented him wit haha list of requests to bolster public faith in Christianity; they noted he had refrained from public endorsements of the tenets of Christianity and beseeched him to declare openly his beliefs. According to Jefferson, "the old fox was too cunning" for the preachers and replied to all their points except the one about his personal faith. Bishop William White of Pennsylvania, Washington's pastor during his presidency in Philadelphia, also stated, "I do not believe that any degree of recollection will bring to my mind any fact which would prove General Washington to have been a believer in the Christian revelation." [3]

I like to use this as an example because it is rather unremarkable among the elite during this period. Politicians were often attacked in newspapers for being secret atheists and personal letters often reveal an ambivalent attitude towards Christianity from many founders. Deism was very common amongst the founders as well, which held to a very different version of divine beliefs than what 21st century Americans would find off.

• When did America become more religious?

I'll answer this in a follow up comment.

1. James Bell, A War of Religion: Dissenters, Anglicans and the American Revolution (New York: Palgrave Macmillan Press, 2008). 18

2. Hoffman, Ronald. A Spirit of Dissent: Economics, Politics, and the Revolution in Maryland. Baltimore: Johns Hopkins University Press, 1973. 9

3. Ron Chernow. Washington: A Life. 2004.

When did America become more religious?

This may seem like a simple question, but it actually is rather complicated. To put it simply, the early part of the 19th century saw religion explode in the newly formed United States. Nathan Hatch's The Democratization of American Christianity is a landmark book in the study of American religion. Hatch's book examined 5 different versions of Christianity and tracks how they grew through the early 19th century. In his book, he shows how quickly some versions of Christianity exploded, especially Methodists and Baptists. Here, Hatch says:

The wave of popular religious movements that broke upon the Unites States in the first half century after independence did more to Christianize American society than anything before or since. Nothing makes that point more clearly than the growth of Methodist and Baptist movements among white and black Americans. Starting from scratch just prior to the Revolution, Methidism in America grew at a rate that terrified other more established denominations. By 1820, Methodist membership numbered a quarter million; by 1830 it was twice that. Baptist membership multiple tenfold in the three decades after the revolution; the number of churches increased from five hundred to over twenty five hundred. [1]

These are just two extremely popular religions that boomed, but most variations of Christianity grew through this period as well.

1. Nathan Hatch. The Democratization of American Christianity. 1990. pp 3