Notes: Regular Members are non-student members whose dues are determined by income level. Highest degree not reported by 13 percent of regular members in 2001; by 2 percent of regular members in 2008; and by 2 percent of regular members in 2015. For each year, less than 0.1 percent of members reported an associate’s degree as their highest degree. “Other professional degree” includes terminal degrees separate from the doctorate.