Here is their count.
Week 1: 88
Week 2: 155
Week 3: 187
Week 4: 191
Week 5: 264
Week 6: 269
Week 7: 299
Week 8: 308
Week 9: 386
Week 10: 388
Week 11: 566
(There are rules to their count, in case you are interested: http://popwatch.ew.com/2011/05/06/summer-movie-body-count/#more-137630)
There are many things that feel not-right about 1) the article(s) at Popwatch, 2) the amount of people we see killed on screen, and 3) how little we seem to notice it. In regard to PG-13 movies, I think that they are frequently worse than R rated movies...probably more often than what we might think. I wonder if the typical PG-13 movie maker falls into the category of Hollywood sell-out, let's-make-alot-of-money more often than the R-rated, there's-an-intended-message-here movie maker? That (possibly unhelpful) question assumes that the better movie is usually the one trying to express something constructive than the one trying to provide a give-em-what-they-want buzz.
Here's their week by week list - http://popwatch.ew.com/