The graph nicely illustrates the inherent contradiction posed by religious zealots who alternatively shout "we are a Christian nation!" and "Christianity is under attack!" We are an overwhelmingly Christian nation—or at least we tell pollsters that we are—that is on a long and steady slide toward atheism, agnosticism, and general secularism. Those who find some sort of strength in the fact that they are currently part of the 77 percent of the nation who call themselves Christian deeply fear the fact that, ten years from now, that number will have been chipped away to 70 percent, and so on.
The numbers are certainly not going up. Astonishingly, the chart shows no bump in post-9/11 religiosity, which means it will take a lot of screaming and fire-breathing and Bible-thumping to reverse the trend.
Below is a corresponding graph showing the concomitant rise in atheism: