Annual years
1960 43.15036006316914
1961 43.753402650085214
1962 44.55102457354113
1963 45.234994148689836
1964 45.832277791473885
1965 46.3940850359602
1966 47.102062040047194
1967 47.20453996272945
1968 48.063035479286974
1969 48.62853433167091
1970 49.50418379497046
1971 48.250651522783265
1972 50.53597196569791
1973 50.992724555366635
1974 51.32255437392873
1975 51.813249322391556
1976 52.30454123698235
1977 52.67734101041228
1978 53.04048878258976
1979 53.382688088680176
1980 53.87836711740482
1981 54.40768243469677
1982 54.63427681951254
1983 54.98050003582739
1984 55.18650291386995
1985 55.19310585782834
1986 55.16752956588283
1987 55.07861834245852
1988 55.199109186860426
1989 55.318134616053065
1990 55.39103925269608
1991 55.241258265488916
1992 55.05015015342002
1993 54.852897984702466
1994 54.7125595329736
1995 54.46808808680942
1996 54.611071586231276
1997 54.6653771841519
1998 54.91702912511068
1999 55.34471392725081
2000 55.76465717273833
2001 56.009226868429494
2002 56.35843155175531
2003 56.67468543772667
2004 56.9971444858111
2005 57.033413710817804
2006 57.83625848401016
2007 58.08495115379451
2008 58.376198231335216
2009 58.71170036692731
2010 59.059051636771535
2011 59.44509488118619
2012 59.639842602036396
2013 59.95026817761183
2014 60.12149823683007
2015 60.35748183796584
2016 60.56408024403011
2017 60.879519339165455
2018 61.08247417530454
2019 61.33856404838313
2020 61.01164076878519
2021 60.67959253823564
2022 61.28382244405371