I am currently working my way through 72 final-year research papers. I have been somewhat shocked by the low level of preciseness when it comes to English grammar: mixing up tenses, there being used instead of their, its being mixed up with it's, and renegade commas and apostrophes appearing at random! Split infinitives and the non-use of the Oxford comma are also commonplace, but only a pedant worries about such grammatical niceties!
Thankfully moves are afoot to improve the grammar of school kids. You can read more on this as well as test your grammar by clicking here.