Year Percent 1950 15.41465 1955 15.47431 1960 16.49248 1965 17.41464 1970 18.23488 1975 18.50833 1980 17.00114 1985 17.13314 1990 21.46162 1995 23.29694 2000 25.49186 2005 26.42476 2010 28.08582 2015 30.11736 2020 31.86265 2025 33.30808 2030 34.25783 2035 35.72449 2040 36.85412 2045 38.24185 2050 40.02879 2055 40.19576 2060 39.01556 2065 38.41952 2070 39.0128 2075 39.1985 2080 39.37516 2085 39.41982 2090 39.27459 2095 39.27469 2100 39.61378