Year % of total population 1960 26.1885964409313 1961 25.8363943871649 1962 25.4371843897576 1963 25.0144391700551 1964 24.5928923591849 1965 24.2306206804877 1966 23.9261950394273 1967 23.6551395000368 1968 23.4698614221273 1969 23.3880000502765 1970 23.3109886460949 1971 23.2004429198545 1972 23.0867491640664 1973 23.0079000499115 1974 23.0057458707761 1975 23.0140240838166 1976 22.9844366858022 1977 22.9551777036474 1978 22.9009906212334 1979 22.8040854307467 1980 22.6901503083422 1981 22.5605386877178 1982 22.4235088738234 1983 22.2106501550338 1984 21.9130453750717 1985 21.6339682630288 1986 21.4032973877542 1987 21.2156663476489 1988 21.0079149461595 1989 20.7028791188072 1990 20.3398922931153 1991 19.9376884711346 1992 19.4817858900238 1993 19.0121378469612 1994 18.5213171579556 1995 18.0128478889523 1996 17.5257243575338 1997 17.0316789990294 1998 16.5197396406793 1999 16.0451936286104 2000 15.6267066978286 2001 15.2088825935435 2002 14.7869228232397 2003 14.3877112905773 2004 14.024731236181 2005 13.7393674638652 2006 13.5675781054839 2007 13.5087408264932 2008 13.5230262544996 2009 13.6080811181998 2010 13.7460029260014 2011 13.8675059292363 2012 13.9936146095852 2013 14.1157160029026 2014 14.143617563499 2015 14.1107706826696 2016 14.0948812337112 2017 14.1013586142904 2018 14.0963652542866 2019 14.0620489208698 2020 14.0190362054997 2021 13.9947290591926 2022 13.9959094378861 2023 13.9700588407075