Year Percent 1950 5.1583 1955 4.72544 1960 4.50212 1965 4.40208 1970 4.55943 1975 4.65204 1980 4.57179 1985 4.50388 1990 4.72886 1995 4.8724 2000 5.11409 2005 5.44892 2010 6.52437 2015 7.28062 2020 8.22916 2025 9.22483 2030 10.25493 2035 11.17318 2040 12.12053 2045 13.05025 2050 14.1562 2055 15.61678 2060 17.04731 2065 18.32948 2070 19.60996 2075 20.93539 2080 22.26937 2085 23.58068 2090 24.86825 2095 26.12859 2100 27.3402