More seriously, here are the details: in question 16 of the full report (pdf) respondents were asked "What is your present religion if any?" 16.1% of the 35,556 individuals questioned replied "unaffiliated" (p. 210), that is, 5,048 (+/- 2% margin of error) individuals self-identified as either atheists, agnostics or someone who believes in "nothing in particular" (p. 177). Of the total number of respondents, 1.6% (or about 589 in absolute terms) said they were atheists, 2.4% (~853) said their were agnostic and 12.1% (~4302) said 'nothing in particular' (p. 217; note: I had to calculate the absolute Ns myself). Then, in questions 30 and 31, respondents were asked "Do you believe in God or a universal spirit?" and "How certain are you about this belief?" (p. 227-228). As I already said above, 21% of atheists (~124) and 55% of agnostics (~469) said they did so believe (p. 9) and, incredibly, 8% of atheists and 17% of agnostics said they were absolutely certain in their belief. A few more crazy statistics: 11% of atheists and 14% of agnostics say they "completely" believe in miracles while 6% of atheists and 7% of agnostics "completely" believe in angels and demons (p. 35). Perhaps most ridiculously of all: 3% of atheists said they think the Bible (or another holy book) is the literal word of God...
A couple of points: firstly, question 16 was 'What is your religion?" and question 30 was "Do you believe in a God or a universal spirit?" So some of those who self-identified as atheist or agnostic might have said yes to q. 30 due to the 'universal spirit' part and since that term is vague and left undefined, it's hard to tell what the answers mean. This explanation, however, is not the whole story: 6% of atheists and 14% of agnostics say they believe in a personal God, while 12% and 36%, respectively, believe in an "impersonal force" (p. 6). In other words, at least 6% of the self-described atheists and 14% of the self-described agnostics need a smack. Some people will no doubt think this result reflects badly on atheists: 'atheists are so silly and confused that they believe in God. Hallelujah!' Well, actually, no: this finding reflects badly on theists: an atheist, by definition, is someone who lacks a belief in God so those who self-identified as atheist and then said they believed in God aren't atheists, they're stupid or deeply confused religious people. That is, these people are theists who don't know what either atheism or agnosticism means.
I want to end on an optimistic note: one of the key findings of World Values Survey is that cultural change occurs through generational replacement, that is, the total incidence of some value or belief alters not because people change their minds, but because the incidence varies between generations and as the oldest generation dies, the total incidence changes as well. Take a simple example: if 5% of generation 1 but 15% of generation 2 believe homosexuality is an acceptable life choice, the total population's tolerance will increase as generation 1 dies and gets replaced by generation 2. (The idea is essentially the same in Max Planck's famous quote: "a new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it"). With generational replacement in mind, have a look at the following table:
Note how the proportion of people who say they're absolutely certain that a personal God exists is much lower in younger than older people: 57% of over 65's but only 45% of 18-29 year olds in the total population are certain in that way. The same pattern (with a couple of exceptions) holds for the religious sub-groups as well. In other words: young Americans are much more doubtful of God's existence. Now have a look at:
We again see the same pattern: 69% of those 65 and over, but only 45% of those between 18 and 29 say religion is very important to them. And again the pattern holds for the different affiliations: younger Americans, in other words, think religion is much less important than older Americans.
While the above data are suggestive, the first Religious Landscape Survey (pdf) contains very solid evidence generational replacement is happening. The report notes:
Important generational differences in religious affiliation are also evident. For example, one quarter of all adults under age 30 are not affiliated with any particular religion, which is more than three times the number of unaffiliated adults who are age 70 and older, and nine percentage points higher than in the overall adult population. (p. 36).These conclusions are clearly borne out in the data:
Atheism and agnosticism is quite a bit more common among 18-29 year olds than among 65 year olds and over. Indeed, fully 25% of those in the youngest cohort are religiously unaffiliated, and the proportions follow the generational replacement pattern perfectly. The bottom line is clear: younger Americans tend to be significantly less religious than older Americans and, as time passes, the proportion unbelievers (and non-fundamentalists) should increase dramatically. Now that's good news indeed.
(I should note that in arguing generational replacement is occurring I have throughout assumed religious beliefs and values remain largely unchanged throughout people's lives. I have assumed, specifically, that younger people's relative irreligiosity is not due to their youth, that is, I have excluded a 'life stages' approach in which people become more religious as they age. This assumption, I contend, is reasonable: the World Values Survey has collected solid evidence that people's fundamental values and beliefs tend not to change after their early-20s. It's important to bear in mind nonetheless that there is room for disagreement here).
(Hat tip: Andrew Dellis).