Year Percent 1950 13.94594 1955 14.29121 1960 12.81126 1965 13.41447 1970 13.74451 1975 14.17473 1980 14.33676 1985 14.54456 1990 14.2758 1995 15.55925 2000 14.00066 2005 11.67232 2010 9.98666 2015 9.26471 2020 8.39718 2025 7.96078 2030 7.31008 2035 6.63727 2040 6.07166 2045 5.68477 2050 5.44949 2055 5.29115 2060 5.13748 2065 4.97486 2070 4.83469 2075 4.75351 2080 4.73577 2085 4.74957 2090 4.75777 2095 4.74141 2100 4.71369