Year Percent 1950 8.69671 1955 8.95811 1960 9.76844 1965 10.77787 1970 12.45009 1975 12.2997 1980 12.41921 1985 12.51962 1990 14.84396 1995 15.91591 2000 16.79894 2005 18.75429 2010 22.90284 2015 25.05846 2020 27.60318 2025 29.31309 2030 29.96206 2035 31.11989 2040 32.86497 2045 34.79102 2050 36.77999 2055 38.47157 2060 39.18372 2065 39.03206 2070 38.7628 2075 38.68529 2080 38.67892 2085 38.78376 2090 38.87689 2095 38.88034 2100 38.89761