The top-level class for religion heavily favors [[Christianity]], dedicating nearly all of the 200 division to it: the world's thousands of other religions were listed under the 290s.<ref>{{Cite web|url=http://bpeck.com/references/ddc/ddc_mine200.htm|title=DDC -– 200 -– Religion|website=bpeck.com|access-date=2018-03-20|archive-date=March 16, 2018|archive-url=https://web.archive.org/web/20180316152154/http://bpeck.com/references/DDC/ddc_mine200.htm|url-status=live}}</ref> For example, Islam is under just DDC 297, despite being almost as large as Christianity by population.<ref>{{Cite news|url=https://www.npr.org/sections/thetwo-way/2015/04/02/397042004/muslim-population-will-surpass-christians-this-century-pew-says|title=World's Muslim Population Will Surpass Christians This Century, Pew Says|work=NPR|access-date=2018-03-20|language=en|archive-date=January 22, 2018|archive-url=https://web.archive.org/web/20180122125353/https://www.npr.org/sections/thetwo-way/2015/04/02/397042004/muslim-population-will-surpass-christians-this-century-pew-says|url-status=live}}</ref> The entire 200 section has remained largely unchanged since DDC 1, since restructuring would pose a significant amount of work for existing libraries. The motivation for this change is ideological rather than technical, as appending significant figures can add space as needed.{{sfnp|Olson|2002|p=22}}
