Year Percent 1950 28.14213 1955 27.34486 1960 26.98435 1965 25.3657 1970 24.63205 1975 26.45923 1980 26.30537 1985 27.8278 1990 28.10265 1995 31.44141 2000 33.11041 2005 31.13341 2010 31.15233 2015 32.63894 2020 33.36443 2025 31.8882 2030 28.19956 2035 24.83942 2040 22.65574 2045 22.22323 2050 23.18921 2055 23.23382 2060 22.60373 2065 21.20171 2070 19.93733 2075 19.58941 2080 20.06732 2085 20.6711 2090 20.79708 2095 20.36021 2100 19.74223