Year % of total population 1960 39.2344820349857 1961 38.9122169891619 1962 38.6520416182486 1963 38.4316522935429 1964 38.2347781373824 1965 38.0593450980166 1966 37.9104592102307 1967 37.790746274895 1968 36.4965212424268 1969 34.3621797276328 1970 32.7216489311738 1971 31.5895191182916 1972 30.7930310320923 1973 30.2224456794989 1974 29.8045552946916 1975 29.4830270485136 1976 29.2461293731286 1977 29.1628764353954 1978 29.2265200917501 1979 29.3694108219257 1980 29.5568848811891 1981 30.1811521750986 1982 31.1532414955268 1983 32.0335301703659 1984 32.8268610924911 1985 33.5153268925204 1986 33.7158038724121 1987 33.5255398630251 1988 33.3598229118224 1989 33.2147959639253 1990 33.086265249446 1991 32.9697572624345 1992 32.8607793761645 1993 32.7575334505173 1994 32.6576282597346 1995 32.5535705188358 1996 32.3776059329857 1997 32.1590579286622 1998 31.9744071643508 1999 31.8180130638182 2000 31.6836486549612 2001 31.5668933859611 2002 31.4652051446821 2003 31.3747183319641 2004 31.2913328920986 2005 30.9642645993581 2006 30.0241031044586 2007 28.8037511000193 2008 27.8159052811795 2009 27.2054278909457 2010 27.1969144179912 2011 27.5748976263541 2012 27.9354028848805 2013 28.2811388270385 2014 28.6123927124539 2015 28.927601400442 2016 29.2253072875454 2017 29.5073186847893 2018 29.7788585747156 2019 30.0471891213492 2020 30.277091624908 2021 30.4651769940562 2022 30.6465995751144 2023 30.8219476758695