Year Percent 1950 16.95691 1955 17.72665 1960 17.90991 1965 17.05532 1970 15.34948 1975 14.48243 1980 15.96614 1985 17.30276 1990 19.25323 1995 22.69185 2000 26.61669 2005 28.60395 2010 30.04089 2015 28.7481 2020 26.01309 2025 23.34903 2030 22.11257 2035 22.53518 2040 24.36485 2045 25.78565 2050 26.36228 2055 26.23702 2060 25.90972 2065 25.5884 2070 25.54741 2075 25.1365 2080 24.58509 2085 24.14998 2090 23.88929 2095 23.74649 2100 23.63186