Year Percent 1950 9.96803 1955 10.25911 1960 10.34217 1965 10.04203 1970 9.68287 1975 9.42437 1980 9.84647 1985 10.89491 1990 10.00424 1995 9.72941 2000 9.45791 2005 8.8343 2010 8.68763 2015 8.38218 2020 8.15837 2025 7.7906 2030 7.42773 2035 7.11011 2040 6.82463 2045 6.56873 2050 6.33404 2055 6.11727 2060 5.90771 2065 5.72195 2070 5.57389 2075 5.44647 2080 5.3432 2085 5.24568 2090 5.15244 2095 5.07379 2100 5.0037