Year Percent 1950 30.32496 1955 30.56248 1960 33.05791 1965 31.5329 1970 29.81061 1975 29.68992 1980 29.35129 1985 28.94073 1990 29.85318 1995 29.9465 2000 30.55363 2005 32.24427 2010 30.77733 2015 28.66092 2020 26.34419 2025 25.47662 2030 23.87953 2035 23.49705 2040 23.27893 2045 23.03278 2050 22.462 2055 22.2223 2060 22.154 2065 22.19716 2070 22.27083 2075 22.26656 2080 22.12135 2085 21.92912 2090 21.79347 2095 21.72318 2100 21.69043