Year Percent 1950 31.07209 1955 29.97167 1960 29.32322 1965 28.65909 1970 27.69513 1975 28.51917 1980 28.65567 1985 28.22597 1990 27.79137 1995 28.74917 2000 28.10083 2005 27.35215 2010 27.0245 2015 28.5373 2020 31.84334 2025 34.9922 2030 36.53766 2035 35.95007 2040 33.7601 2045 31.30289 2050 29.37978 2055 28.06413 2060 26.46231 2065 24.82897 2070 23.44784 2075 22.49891 2080 21.88231 2085 21.40353 2090 20.98678 2095 20.64078 2100 20.40092