Year Percent 1950 15.39784 1955 15.81159 1960 15.93511 1965 15.38924 1970 15.36067 1975 15.12777 1980 14.88092 1985 15.30926 1990 16.51155 1995 18.77377 2000 21.53208 2005 24.60145 2010 25.67921 2015 26.09908 2020 26.66235 2025 28.14634 2030 29.8501 2035 29.77586 2040 28.35387 2045 25.80965 2050 24.72243 2055 25.2563 2060 26.09981 2065 26.03786 2070 25.1067 2075 24.0878 2080 23.74696 2085 23.95754 2090 24.25422 2095 24.24646 2100 23.89638