Year Percent 1950 4.21051 1955 4.59873 1960 4.521 1965 4.32593 1970 4.56517 1975 4.65206 1980 4.85956 1985 5.3089 1990 6.12218 1995 7.18811 2000 8.92434 2005 10.71538 2010 13.2729 2015 16.23573 2020 20.74264 2025 25.09909 2030 29.23775 2035 32.87088 2040 35.32474 2045 37.58998 2050 38.69301 2055 40.37702 2060 41.17373 2065 40.70623 2070 39.86221 2075 39.15212 2080 38.75841 2085 38.60307 2090 38.73408 2095 38.87829 2100 38.84356