Annual years
1960 36.449395919628905
1961 36.76407254219356
1962 37.56640245342807
1963 37.87866005666239
1964 38.10102266393706
1965 38.427363316756484
1966 38.67589917708798
1967 38.014845715364984
1968 38.664320803494284
1969 38.969390266644275
1970 39.89009419116686
1971 40.46609095086741
1972 41.16319097696989
1973 41.815577815131256
1974 42.451510845140355
1975 43.11312362005278
1976 43.8516011602725
1977 44.50695004325484
1978 44.988173831878754
1979 45.3865610916076
1980 45.70329054057968
1981 46.03038897616168
1982 46.24279308344382
1983 46.498480944674114
1984 46.64511259970675
1985 46.688084711637
1986 46.757499803685114
1987 46.80572347822744
1988 47.115535683379136
1989 47.279733441752136
1990 47.152056124936884
1991 47.21755798208769
1992 47.276526062265084
1993 47.39136492587189
1994 47.284382883718095
1995 47.38697296631699
1996 47.51506214675134
1997 47.70111057494718
1998 48.10186387570734
1999 48.524148583851265
2000 49.07771249905159
2001 49.46567698791821
2002 49.8332997902483
2003 50.29497067379433
2004 50.757006716806224
2005 51.296532149264806
2006 51.834634242423455
2007 52.25778250083005
2008 52.741954744970734
2009 53.24110075498884
2010 53.65788417724439
2011 54.10131434381043
2012 54.42209012481785
2013 54.73281544312579
2014 54.9676741841976
2015 55.233506947308754
2016 55.71710556120907
2017 55.94266378321405
2018 56.271812470012826
2019 56.57739212259525
2020 56.131022627744386
2021 55.90341913181697
2022 56.556727337476126