Annual years
1960 46.22789132098803
1961 46.54233098338957
1962 46.88527694324949
1963 47.187179156833324
1964 47.69949531899309
1965 47.807094707005014
1966 47.777304026955306
1967 48.01519102770275
1968 48.44030123979095
1969 48.542218831156276
1970 48.92553698087063
1971 49.50009731007087
1972 49.50700378935333
1973 50.103297980453526
1974 50.23734077964083
1975 50.484002715741326
1976 50.947728339706366
1977 51.47797304369472
1978 51.60926316385559
1979 51.85304977037558
1980 52.07609251920815
1981 52.209476258461656
1982 52.188225280840385
1983 51.58250837359558
1984 51.434756934589075
1985 51.608280044030145
1986 52.2318694997475
1987 52.679929722592256
1988 52.2507895423155
1989 53.28316471692036
1990 53.30253431575152
1991 53.30873661822025
1992 53.281669542089084
1993 53.67282525079816
1994 54.28838789778534
1995 54.00329615791167
1996 54.081087533764446
1997 54.3782007379501
1998 54.164337000250846
1999 54.87923102629131
2000 55.509639316699236
2001 55.72925521503298
2002 56.14948004720196
2003 56.419036453388344
2004 56.665498658649
2005 57.05810557151295
2006 57.54270914152649
2007 58.00940644920565
2008 58.01868742884508
2009 59.06225345394925
2010 59.3081381864351
2011 59.96632784371176
2012 60.16658424279599
2013 60.46601388694744
2014 60.70998735538693
2015 61.01446364341172
2016 61.292380360629714
2017 61.657084412036525
2018 61.9720515279674
2019 62.269780743055236
2020 61.762486987637644
2021 61.253265735449126
2022 61.79258830055621