Annual years
1960 39.936486093579084
1961 40.19358292411599
1962 40.75615612397444
1963 40.92132714231309
1964 41.33880116619938
1965 41.471011409072894
1966 41.470090133684124
1967 41.56334730828552
1968 42.010892654183834
1969 42.248357847763934
1970 42.804827774353946
1971 43.29687498558809
1972 43.41732319166781
1973 44.211278705831134
1974 44.43248112988704
1975 44.817958491903894
1976 45.405262947701054
1977 45.807338130189784
1978 46.024703404197346
1979 46.5120971018203
1980 46.88373130213431
1981 47.22347877827711
1982 47.433636057279735
1983 46.58913154514721
1984 46.523234345850724
1985 46.75368631531391
1986 47.12415713823102
1987 47.33626738834285
1988 46.998559426373305
1989 47.93043182867709
1990 47.79775987291264
1991 47.746964067713606
1992 47.500252054098915
1993 47.7004039847874
1994 48.171677255328504
1995 48.2531130780926
1996 48.207112631754576
1997 48.42095219621785
1998 48.09347554728754
1999 48.87103536639768
2000 49.76667094571204
2001 50.12352093417093
2002 50.48915625930067
2003 51.01322919947332
2004 51.51093555422513
2005 52.11547430633518
2006 52.869201559909236
2007 53.46304769464436
2008 54.04304501344874
2009 54.72921512190718
2010 55.3262066424181
2011 55.967547393212385
2012 56.49453588915654
2013 56.94217539837116
2014 57.36744372358984
2015 57.76649486801431
2016 58.262184315743106
2017 58.657879819470786
2018 59.01098213503432
2019 59.364417392891276
2020 58.90287981044087
2021 58.26433575250977
2022 58.807849649292166