Annual years
1960 41.999325391616466
1961 42.500036713077876
1962 43.164303678190464
1963 43.44903873747101
1964 44.07100770758871
1965 44.25626754397945
1966 44.754790340294804
1967 45.06763205394497
1968 45.581637080131046
1969 45.922884594601676
1970 45.532468357446845
1971 42.20532751071847
1972 46.88733192271881
1973 47.41108834358728
1974 47.552105321613844
1975 47.79574854693937
1976 48.33934173116746
1977 48.80434412778062
1978 49.07004954702507
1979 49.44361408702489
1980 49.964907373132554
1981 50.307741243286344
1982 50.466679575287166
1983 50.27658460261292
1984 50.306911480611575
1985 50.586441489609314
1986 51.02965875694078
1987 51.3348830377208
1988 51.26780333525353
1989 51.966873368973395
1990 52.17726247328733
1991 51.983246853512945
1992 52.28579213680365
1993 52.56855730845991
1994 52.971599429368936
1995 53.12445164373633
1996 53.2857356888658
1997 53.62736807266499
1998 53.80385407156657
1999 54.79352792778858
2000 55.33614976859317
2001 55.70808004483993
2002 56.06826571337077
2003 56.46318221831801
2004 56.781766925115164
2005 57.13203085983144
2006 57.71495224299507
2007 58.002198787334855
2008 58.18794013237218
2009 58.786513777885986
2010 59.22204705980754
2011 59.71270814093725
2012 59.92848341158407
2013 60.14068109041266
2014 60.467518962982865
2015 60.779636277688184
2016 61.18949398061345
2017 61.51932194256989
2018 61.862584840627505
2019 62.16441459023181
2020 61.67430830116674
2021 61.29119501537765
2022 61.89483006724305