Well, whatever it is, Evangelicals are sure there's a lot more of it than everyone else. A recent survey by Ellison Research (hat tip to Episcopal Cafe)shows that there are many things that most of the population define as sin (even the for the non-religious "the concept is commonly accepted even among those who are not religiously involved", according to Ellison).
(Update - for some reason the tables didn't display properly, so I fixed them...)
The data are sliced and diced quite a few ways, but I thought I'd highlight a few things. First, the overall numbers:
|Using hard drugs such as cocaine, heroine, meth, LSD, etc.||65|
|Not saying anything if a cashier gives you too much change back||63|
|Having an abortion||56|
|Homosexual activity or sex||52|
|Not reporting some income on your tax returns||52|
|Reading or watching pornography||50|
|Sex before marriage||45|
|Sexual thoughts about someone you are not married to||43|
|Doing things as a consumer that harm the environment||41|
|Not taking proper care of your body||35|
|Telling a little white lie to avoid hurting someone's feelings||29|
|Not attending church or religious worship services on a regular basis||18|
|Watching an R-rated movie||18|
|Playing the lottery||18|
|Being significantly overweight||17|
|Not giving 10% of your income to a church or charity||16|
|Drinking any alcohol||14|
|Working on Sunday/the Sabbath||14|
|Spanking your child when he/she misbehaves||7|
|Making a lot of money||4|
We can see, then, that the average person has some peculiar standards for "sin". Not correcting an error in getting too much change is more sinful than having an abortion. A sixth of people think being overweight is sinful. The top of the list is dominated by big issues: Adultery, Racism and Drug use.
And it's important to bear in mind that just because someone may believe something is sinful, they wouldn't necessarily impose that belief on others, or want it prohibited by legislation.
I have to wonder about the "sexual thoughts about someone you aren't married to" item. I presume the question is meant to refer to married people, because if 43% of people think that's a sin for a single person thinking about another single person, i think we have a serious problem. Not to mention every single episode of Baywatch must have caused more backsliding than the slippery slopes in It's a Knockout...
It gets interesting when we look at the breakdown by demographics. You can look up many of those on the Ellison site, but one that caught my eye was the breakdown by Evangelical/Not Evangelical. There are lost more religious oriented breakdowns, but none as dramatic as that.
Here's the same list, with Evangelical and the difference between Evangelical and All added, ordered by the magnitude of the difference (i.e., the biggest likely cultural disconnects between Evangelicals and the rest of society)...