Year Percent 1950 13.44664 1955 13.52445 1960 14.03716 1965 14.72665 1970 15.11913 1975 15.14391 1980 13.92668 1985 14.86195 1990 17.75793 1995 18.5896 2000 19.23028 2005 19.50035 2010 20.75441 2015 21.7602 2020 23.4076 2025 25.63761 2030 27.54922 2035 28.9826 2040 29.94045 2045 30.59017 2050 31.02492 2055 31.39909 2060 31.36647 2065 31.36108 2070 31.7356 2075 32.20641 2080 32.7187 2085 33.13562 2090 33.49548 2095 33.8443 2100 34.25418