https://nces.ed.gov/programs/digest/d16/tables/dt16_318.30.asp does say that, in 2014-2015, 109,896 biological science majors earned bachelor’s degrees.
https://www.aamc.org/download/321496/data/factstablea17.pdf says that in 2018-2019, 11,843 biological science majors matriculated to MD medical school (out of 29,443 who applied to MD medical school).
https://www.aacom.org/docs/default-source/data-and-trends/2015_mat.pdf?sfvrsn=25da5497_8 says that in 2015, 5,848 biological science majors matriculated to DO medical school (out of 16,967 who applied to DO medical school).
Some applicants may have applied to both MD and DO medical schools.
But it does look like there are almost a hundred thousand bachelor’s degree graduates in biological science each year who do not go on to (MD or DO) medical school (although not all of them applied or were initially pre-med but did not apply). So your original “hundreds of thousands” may be more correct if you are counting a few years’ worth of biological science graduates.