Values and volunteerism.
D000368:Aged; D001290:Attitude; D004651:Employment; D006077:Government Agencies; D006801:Humans; D007182:Income; D007391:International Cooperation; D007899:Leisure Activities; D008875:Middle Aged; D009790:Occupations; D009938:Organizations; D012179:Retirement; D012945:Social Values; D012947:Social Work; D013997:Time Factors; D014481:United States; D014838:Volunteers / Q000706:statistics & numerical data*