Roughly what percentage of Jews killed during the Holocaust were killed in camps, compared to just being shot on sight or brutalized to death or something else?

The US Holocaust Memorial Museum has a page that has some grim statistics both for the total numbers of victims of the Nazis, and a further breakdown for the Jewish victims of the Holocaust.

Of the roughly 6 million Jewish victims, some 2.7 million died in the major extermination centers (the Auschwitz complex, Treblinka, Belzec, Sobibor and Chelmno), or about 45%. Some further 150,000 died in various concentration camps (2.5%), and about 800,000 (13.3%) died in ghettoes, which in many ways operated as makeshift camps. About 1.6 million (26.9%) were murdered in various shooting operations, torture or using mobile gas wagons. A final 500,000 (or 8.33%) died in "other" circumstances, which were mostly mass shootings, deaths in anti-partisan actions, deaths in labor battalions, or deaths from camp evacuations.