Year Percent 1950 6.7663 1955 6.70257 1960 7.01213 1965 7.43873 1970 7.42358 1975 6.85146 1980 6.35956 1985 6.08639 1990 7.16225 1995 6.4898 2000 5.80407 2005 5.08183 2010 4.96748 2015 5.71087 2020 6.99315 2025 8.41196 2030 9.7207 2035 10.85657 2040 11.84598 2045 13.23901 2050 15.27197 2055 16.90075 2060 18.15931 2065 18.88753 2070 20.11646 2075 21.88145 2080 23.5855 2085 25.01446 2090 26.20765 2095 27.42731 2100 28.82517