Year Percent 1950 6.24934 1955 5.52127 1960 5.13281 1965 4.95085 1970 4.93133 1975 4.98605 1980 4.96339 1985 4.91001 1990 5.14153 1995 5.11249 2000 4.88864 2005 4.75454 2010 4.69463 2015 4.80118 2020 4.98967 2025 5.29574 2030 5.7352 2035 6.34774 2040 7.07894 2045 7.82054 2050 8.51687 2055 9.08337 2060 9.69526 2065 10.56303 2070 11.61741 2075 12.66169 2080 13.63964 2085 14.58461 2090 15.57026 2095 16.60731 2100 17.68123