Year | Value | 2022 | 32.966124667358 | 2021 | 33.007651709895 | 2020 | 31.466444344292 | 2019 | 32.033618540302 | 2018 | 35.123728070985 | 2017 | 37.285647797038 | 2016 | 34.46681260427 | 2015 | 32.04356935445 | 2009 | 23.929875615056 | 2008 | 18.033125311641 | 2007 | 23.626605923963 | 2006 | 22.686884629446 | 2005 | 24.162606175355 | 2004 | 22.118897319308 | 2003 | 21.65615495032 | 2002 | 21.311268790083 | 2001 | 22.954101782154 | 2000 | 22.099655898193 | 1999 | 23.386540046989 | 1998 | 22.64724405524 | 1997 | 22.202647594541 | 1996 | 21.600540088967 | 1995 | 20.831570554921 | 1994 | 24.379273038111 | 1993 | 25.618138578087 | 1992 | 24.453690210743 | 1991 | 23.612689563434 | 1990 | 23.700491462285 | 1989 | 23.580437180505 | 1988 | 24.703995934249 | 1987 | 24.16404001404 | 1986 | 23.684090246522 | 1985 | 23.703547206871 | 1984 | 24.145333303304 | 1983 | 26.692167559835 | 1982 | 28.28235105014 | 1981 | 26.773870511366 | 1980 | 25.736137334561 | 1979 | 22.675995160501 | 1978 | 11.152297767894 | 1977 | 5.1314760961075 | 1976 | 2.9084849518183 | 1975 | 7.5378968253329 |
|