What percent of the population in the United States has a Ph.D?

Question

What percent of the population in the United States has a Ph.D?

Answer 1

There's a couple of statistics that apply here:

(1) The percentage of the total population (304 million) that have PhD's is estimated at less than one-half of one percent

(2) The percentage of the total American workforce (about 155 million) that have PhD's is estimated at 1 percent.

FYI:

(3) About 27 percent of the American workforce has completed a Bachelor's degree.

(4) About 16 percent of the American workforce has completed a Master's degree.

Answer 2

http://www.bls.gov/opub/ooq/2002/winter/...  (some info)  

http://www.census.gov/ (search this site, the info is here, will take some searching)