For every React there are 1000 other open source projects run entirely by volunteers. I am curious if there is actual data on the number of man-hours that are

For every React there are 1000 other open source projects run entirely by volunteers. I am curious if there is actual data on the number of man-hours that are spent on open source per year, and how many of those are funded by corporations. My guess is that it is less than 1%.