I don't have concrete statistics for you, but I can point your toward John Brewer's The Sinews of Power. Brewer looks at the the British state in the 18th century, and concludes that it was a "fiscal-military" state, a political and economic entity that existed to raise taxes, borrow money, and fight wars. It became quite effective at this over the course of the 18th century, and its ability to collect and spend taxes, according to Brewer, allowed the government to borrow larger and larger sums from London bankers. France and other European powers were unable to match Britain's fiscal capacity, and this--according to Brewer--explains why Britain generally got the better of France from 1689 to 1815, when the two countries were at war most of the time.

The taxes, Brewer argues, were primarily excise taxes; that is, taxes tied to the production of goods, but typically passed along to the consumer through a modest increase in prices. They were on items like candles, paper, sugar, and so on, coming to include many of the products that were driving the expansion of Britain's economy at the same time. They allowed the state to borrow ever larger sums of money because each major loan taken out was attached to a specific excise tax. Thus, lending the government money was like getting a very secure annuity, funded by taxes and protected by the machinery of government.

This practice allowed Britain to double its national debt each time it fought a new round with France, and after about 1720 the Exchequer gave up actually trying to pay off the principal, and instead focused on simply paying interest. Nevertheless, it was still necessary to expand base from which taxes were collected, and this involved extending taxes to new products and new parts of the realm--including the American colonies. Taxation had generated considerable opposition and even contributed to outright rebellion in Scotland, but extending the machinery of the fiscal-military state to North America was a logical extension of the processes that had been occurring within the Archipelago for generations at that point.

So, given the intensification of fiscal apparatus in Britain in the 18th century, and that the taxes of the 1760s and 1770s could be viewed as ways to extend that apparatus to North America, it certainly makes sense to conclude that the average Briton paid more in taxes than the average colonist.

The complaints of the colonists were not so much about the level of taxes, as about who had the right to impose them. The colonists believed that only their own colonial legislatures should be able to impose taxes (unless the British were willing to allow them to elect their own representatives to Parliament).

The British organized the tea tax, for example, such that the taxed tea was cheaper than any tea ever landed in the colonies before, and cheaper than smuggled, untaxed, tea. The colonists didn't care. They still dumped it into Boston harbor.

Incidentally I was just looking into the rather narrower topic of taxation on tea specifically (because as every schoolchild is taught, taxes on tea were a catalyst for the American Revolution). I found an interesting source here.

The link is to a pretty well-cited study into the issue of how much Britain was actually taxing tea before the Boston Tea Party. If you read through it, you'll probably come away with two impressions: First, nobody can be sure exactly how much taxes were being paid on tea, because of how labyrinthine, ambiguous, and piecemeal the taxes were. Second, all the evidence suggests that tea was cheaper in the colonies than it was in Britain.

So one interpretation of this is that the colonists were less upset about the cost of the taxes (in the case of East India Company tea, tax policy effectively worked as a subsidy in the colonists' favor) and more upset "by the principle of the thing," as Americans characteristically say. "No taxation without representation" wasn't just rhetoric; it was a cornerstone of political legitimacy since the Magna Carta, to say nothing of our innate sense of fairness.

Now a second interpretation, and an important and well-founded one, is that colonists were pissed about the taxes because they interfered with smuggling. Smuggling was big business in the colonies. It was especially big in New England. John Hancock, one of the principal financiers of the Sons of Liberty, made his fortune (as his father had before him) by smuggling. So, although the Sugar Act of 1764 reduced taxes on non-British sugar, it also empowered British officials to more effectively enforce the tax. This hit the smugglers pretty hard, and it meant colonists were paying more in taxes even though the tax rates were technically lower. Later, Britain started cutting the East India Company a deal to sell cheap tea to the colonists. It seems pretty clear to me (and it seemed pretty clear to colonists at the time), that one of the objectives of this policy was to undercut the price of smuggled Dutch tea. So we need to look past rates of taxation to understand why they could have triggered a revolution.

Then there's also the issue of colonial-era finance and "monetary policy," if you will. The colonies had a lot of natural resources, but they didn't have gold and silver mines. A lot of colonists in rural areas used bartering more often than cash. Even in more developed areas, colonists often relied on local currencies, or "Bills of Credit," which were nigh impossible to regulate. In 1764, Britain passed the Currency Act, which basically said that the colonists were going to need to conduct trade and pay taxes in British pounds sterling -- no more of this local currency funny business. But even a small tax is a huge burden if you have to pay it with a type of money you can't get.

I think there's also a larger point to be made here that taxes are not just about money. They are about economic freedom. Taxes can be used to pick winners and losers in a marketplace, which was literally what the Tea Act of 1773 was doing. They can be used to interfere with the development of a professional class, which is what the Stamp Act of 1765, with its taxes on diplomas and legal documents, surely would have done had it ever been effectively enforced. They can be used to pigeonhole an entire industry into serving imperial interests, which is what the Sugar Act of 1764 was doing. Remember that the Revolution started in Boston. Boston had a merchant economy. Americans today like to talk about the importance of economic freedom, but it's nothing compared to the economic freedom of a Boston-based merchant marine in 1750. Yes, there were laws saying that you had to trade with Britain and its territories, but the ocean is big, and Britain was far, far away. In the 1760s, Britain started to chip away at this freedom in very conspicuous and heavy-handed way. When the colonists objected that they deserved a say in these sorts of decisions, the British government responded with a level of arrogance that would have pissed off anyone.

TL;DR: Yes, the colonists had lower rates of taxation than the people of Britain. But that doesn't mean taxes were a red herring. Remember that taxes are about much more than money.