Year % of total population 1960 31.415877862595416 1961 31.14956818181819 1962 30.73216525821596 1963 30.351414725069898 1964 30.00522407407407 1965 29.666319214764837 1966 29.358406909613254 1967 29.0580067560189 1968 28.775984075839002 1969 28.51791114097228 1970 28.26738287829043 1971 28.001521677054996 1972 27.703981372200026 1973 27.450982904438366 1974 27.236254813135787 1975 27.043065638905983 1976 26.856398267358294 1977 26.674549785943185 1978 26.48433254851583 1979 26.274085505541443 1980 26.05827097015787 1981 25.914356008003647 1982 25.927510174666207 1983 25.92284167844665 1984 25.88633221410231 1985 25.832420458201895 1986 25.77773666689508 1987 25.728360156015494 1988 25.67697800077631 1989 25.6161922154204 1990 25.546001188591603 1991 25.54021995024214 1992 25.55923628320622 1993 25.586251949847583 1994 25.609996034787073 1995 25.631588463302474 1996 25.656244654395664 1997 25.68030044916269 1998 25.6961765322056 1999 25.70164314498985 2000 25.70146521508659 2001 25.708085361026946 2002 25.76059222968371 2003 25.802340638245873 2004 25.817756095999684 2005 25.802415269655377 2006 25.774876977958748 2007 25.85986313041601 2008 25.94399387965715 2009 26.03621411494298 2010 26.122612007243053 2011 26.209691582879913 2012 26.298911236013883 2013 26.394913207782782 2014 26.474442132074 2015 26.53984409014903 2016 26.615438219888976 2017 26.712683608416548 2018 26.830458476110202 2019 26.958688199607376 2020 27.137181167537854 2021 27.429134823689783 2022 27.379222905695443 2023 27.404482809070956