The same church that demands a 10% tithe from it's members, yet only gives a fraction of 1 percent of its income to "others more in need". So there's a few million more "exceptions" for your "science" to chew on, not to mention all the other religious giving which accounts for far more than half of all charitable giving in the US. I also suspect that pretty much all charitable giving in the US has a lot to do with tax write-offs unless there's a significant number of people out there giving money away and not claiming it.