I read recently where 4000 or so college students die every year.
That's probably accurate...I found one source that seemed to say that the death rate per college student was about 22.4 per 100,000. And the Mormons have had 10 this year (more than one per month avg) among about 75,000. So the Mormons would need to have 16-17 deaths -- 6 or 7 more in the remaining three months of 2013 -- to equal a rate equivalent.
But these Lds missionaries are your more "valiant" Mormons ... the BYU types. So a fair comparison would be to compare the death rate among BYU students vs. Lds missionaries. I presently don't have those stats...but could easily conclude that it would have been safer for Lds missionaries to be BYU students in 2013.
Your 4,000 deaths per year among college students could be accurate...there's almost (at least) 17.5 million students.
******
Btw...for more on these missionary deaths, See: With 10 deaths this year: Are Mormon missionaries safe?