Year Percent 1950 13.10641 1955 12.78631 1960 12.5326 1965 12.70105 1970 13.1808 1975 13.30011 1980 13.02599 1985 12.37506 1990 11.7538 1995 11.82878 2000 12.04389 2005 12.38653 2010 13.06359 2015 13.90921 2020 15.38274 2025 17.28414 2030 19.1491 2035 21.15654 2040 22.88027 2045 24.22123 2050 24.88771 2055 25.0381 2060 25.01421 2065 24.87575 2070 24.98031 2075 24.99455 2080 24.8329 2085 24.57008 2090 24.28159 2095 24.01001 2100 23.76016