Year Percent 1950 4.76445 1955 4.47009 1960 4.14853 1965 4.11409 1970 4.16721 1975 4.28951 1980 4.45515 1985 4.73789 1990 5.51356 1995 5.75247 2000 6.1045 2005 6.65769 2010 7.11963 2015 8.55087 2020 10.30089 2025 11.99481 2030 13.85881 2035 16.21649 2040 19.00278 2045 22.19451 2050 25.38501 2055 28.29531 2060 30.83106 2065 33.00318 2070 35.07988 2075 36.87645 2080 38.3804 2085 39.54591 2090 40.43796 2095 41.12731 2100 41.68008