Year Percent 1950 14.51789 1955 14.89326 1960 14.85096 1965 14.6333 1970 14.36428 1975 14.98083 1980 14.54539 1985 13.97226 1990 13.73843 1995 13.20056 2000 13.68273 2005 15.10617 2010 17.08002 2015 19.37154 2020 21.60686 2025 23.4326 2030 24.90942 2035 26.34902 2040 27.3453 2045 27.89981 2050 27.90636 2055 27.6103 2060 27.02895 2065 26.2456 2070 25.59227 2075 24.91424 2080 24.1639 2085 23.48578 2090 22.94372 2095 22.5595 2100 22.29765