Is it a thick envelope or a thin envelope? Would-be members of the Harvard College class of 2016 are earning via letter or e-mail today whether they have been accepted to the prestigious Cambridge school. Out of 34,302 applicants, Harvard accepted 2,032, or 5.9 percent, the university said in a statement. “We have always been conservative about the number of acceptances sent out this at this time of year in order to avoid the possibility of overcrowding. Harvard’s high graduation rate - typically 97 to 98 percent - leaves little margin for error,’’ William R. Fitzsimmons, the school’s dean of admissions and financial aid, said.