Year Percent 1950 9.88618 1955 10.38867 1960 13.49741 1965 14.91153 1970 14.72226 1975 14.08087 1980 13.74449 1985 12.867 1990 12.4801 1995 12.09996 2000 11.35823 2005 8.46871 2010 7.52381 2015 7.73032 2020 7.83954 2025 7.40306 2030 7.01813 2035 6.29103 2040 5.74386 2045 5.60243 2050 5.6643 2055 5.67903 2060 5.56728 2065 5.36076 2070 5.16941 2075 5.10267 2080 5.15521 2085 5.22014 2090 5.21656 2095 5.13385 2100 5.03003