Year Percent 1950 5.64022 1955 5.11346 1960 4.86435 1965 4.73773 1970 4.671 1975 4.72241 1980 4.98039 1985 5.44118 1990 6.5546 1995 7.30737 2000 8.21157 2005 9.12471 2010 10.0282 2015 11.13382 2020 12.24604 2025 13.51654 2030 14.90466 2035 16.48701 2040 18.20069 2045 19.91587 2050 22.12224 2055 25.28104 2060 28.62224 2065 30.97792 2070 32.94565 2075 34.72586 2080 36.49559 2085 37.98789 2090 39.08509 2095 39.83453 2100 40.36286