Religion is highly variable between people, and it touches not only their intellectual position, but also their internal and external identity. Any assessment will be impacted by a large number of factors. One common way of assessing people's religiousness, spirituality, and affiliations is asking them to directly self-identify in interviews and polls. According to General Social Survey data, which allowed for degrees of religiosity to be expressed, 21.5% of Americans consider themselves not religious, 25.1% were slightly religious, 37.5% were moderately religious, and 15.5% were very religious in 2018. Irreligiousness is highest among young healthy unmarried educated white males. Overall, approximately 80% of Americans described themselves as both religious and spiritual to varying degrees. According to the 2010–2014 wave of the World Values Survey, 67.9% of Americans considered themselves as a religious person, 27.7% were not a religious person, and 4.5% were a convinced atheist. In the 2005–2009 wave: 72.1% of Americans considered themselves as a religious person, 24.4% were not a religious person, and 3.5% were a convinced atheist. According to Pew's study on religious and spiritual identity, the number of Americans who consider themselves religious (irrespective of whether they are affiliated or spiritual, or believe in one or more Gods or a higher power) had dropped from 65% in 2012 to 54% in 2017. 27% were spiritual but not religious and another 18% were neither. According to the Win-Gallup International polls, those who self-identified as religious person were at 73% in 2005, 60% in 2012 and 56% in 2015 and in 2017. In the 2012 poll, 30% were not a religious person and an additional 5% identified as an atheist. In the 2017 poll, 32% were not a religious person and an additional 7% identified as atheist. However, researchers have advised caution with WIN/Gallup International figures since other surveys like the World Values Survey, which have used the same wording for decades and have bigger sample sizes, show differences in results at the global level. It is worth noting that about half of "not religious" people do actually identify/affiliate themselves with established religious groups and most believe in God. Polling organizations sometimes generate their own abstract versions of what "religious" and "nonreligious" is using variable and inconsistent criteria. According to a 2017 report by Gallup, church attendance and the importance of religion American's lives were interpreted as measure of religiosity.