This is unprecedented because it's simply not true. The best statistic I could find for this is 11%. Even 11% seems like a very high number based on my personal experience. As an American who has lived in different parts of America my whole life (and currently living in a high-tourist city with people from all over the US), I can say that most people in most parts of the US do not believe that the rapture will happen within their lifetime.
http://www.publicpolicypolling.com/pdf/PPP_Release_US_0602.p...
http://www.pewforum.org/uploadedfiles/Topics/Issues/Politics...
41% in no way jibes with my experience, even as someone who grew up attending white rural evangelical churches. You might get 41% (or much higher) to say it might occur, but I am seriously skeptical of "definitely" percentages.
The survey I linked has some interesting facts about American Christian beliefs about science. Strong (79%+) majority believes global warming is a serious problem, for example. Even a slim majority believes in evolution.
In any case, that's not the scary poll. It's polls like this one that are scary: http://www.huffingtonpost.com/2012/03/12/interracial-marriag...