Year Percent 1950 4.89138 1955 4.5086 1960 4.15543 1965 3.85077 1970 3.65159 1975 3.50948 1980 4.4948 1985 3.8893 1990 3.914 1995 3.64315 2000 3.9918 2005 3.44994 2010 3.69499 2015 4.60701 2020 6.07745 2025 7.5151 2030 9.23053 2035 11.24365 2040 13.41191 2045 15.56246 2050 17.76062 2055 19.76841 2060 21.32142 2065 22.69086 2070 23.93809 2075 25.4371 2080 26.7895 2085 28.03411 2090 29.13357 2095 30.08432 2100 30.91288