Year Percent 1950 6.04148 1955 5.60692 1960 5.35284 1965 5.16962 1970 5.04083 1975 5.84167 1980 5.18348 1985 5.17456 1990 5.66535 1995 5.98562 2000 5.64405 2005 6.17676 2010 6.80626 2015 8.06148 2020 9.33214 2025 9.96067 2030 10.14219 2035 9.43581 2040 8.98445 2045 10.48884 2050 12.42144 2055 15.34871 2060 18.41941 2065 20.66541 2070 21.99126 2075 22.91706 2080 24.13154 2085 25.73895 2090 27.5115 2095 29.02578 2100 30.0684