Year Percent 1950 28.57609 1955 27.57287 1960 31.85661 1965 29.96239 1970 27.72513 1975 29.13039 1980 29.27986 1985 32.4163 1990 32.53574 1995 31.67078 2000 31.36493 2005 32.06637 2010 33.38283 2015 32.68802 2020 30.13556 2025 27.50346 2030 26.16701 2035 27.6171 2040 29.87096 2045 31.16796 2050 29.96372 2055 27.52783 2060 26.42777 2065 26.44723 2070 26.89715 2075 26.96461 2080 26.32405 2085 25.25658 2090 24.28764 2095 23.78146 2100 23.69813