Most of the remainder of the population had no religious affiliation; the 2008 American Religious Identification Survey (ARIS) placed Oregon as tied with Nevada in fifth place of U.S. states having the highest percentage of residents identifying themselves as "non-religious", at 24 percent. Secular organizations include the Center for Inquiry (CFI), the Humanists of Greater Portland (HGP), and the United States Atheists (USA).
