Year years 1960 42.692 1961 42.882 1962 43.154 1963 43.372 1964 43.702 1965 43.97 1966 44.373 1967 44.823 1968 45.284 1969 45.666 1970 46.12 1971 46.587 1972 47.089 1973 47.597 1974 48.099 1975 48.729 1976 49.328 1977 49.76 1978 50.232 1979 50.765 1980 51.227 1981 51.764 1982 52.256 1983 52.635 1984 53.089 1985 53.432 1986 53.713 1987 54.051 1988 54.348 1989 54.39 1990 54.37 1991 54.268 1992 54.299 1993 54.195 1994 54.037 1995 54.037 1996 54.098 1997 54.192 1998 54.199 1999 54.538 2000 54.742 2001 54.86 2002 55.311 2003 55.639 2004 55.569 2005 55.962 2006 56.222 2007 56.511 2008 56.695 2009 57.011 2010 57.304 2011 57.925 2012 58.073 2013 58.684 2014 58.853 2015 59.396 2016 59.55 2017 60.154 2018 60.244 2019 60.901 2020 61.035 2021 61.619 2022 61.588