Year | Value | 2022 | 2.1332210334571 | 2021 | 2.2213351596189 | 2020 | 2.506732074866 | 2019 | 2.3309773833403 | 2018 | 2.3968817601241 | 2017 | 2.4421228867188 | 2016 | 2.4287869470889 | 2015 | 2.6315571893041 | 2014 | 2.5340768962692 | 2013 | 2.390431209787 | 2012 | 2.2810010722365 | 2011 | 2.1954745883593 | 2010 | 2.3543129569036 | 2009 | 2.5595884576289 | 2008 | 2.2573149709333 | 2007 | 2.2848592225164 | 2006 | 2.2976052434369 | 2005 | 2.3900677103718 | 2004 | 2.4321542337268 | 2003 | 2.5096251970497 | 2002 | 2.5434980837131 | 2001 | 2.5788237122951 | 2000 | 2.5842896044122 | 1999 | 2.6958049110636 | 1998 | 2.8494208701863 | 1997 | 2.7703870321003 | 1996 | 2.6525839807705 | 1995 | 2.7802048464295 | 1994 | 2.5783481724718 | 1993 | 2.7057311466876 | 1992 | 2.9015628398088 | 1991 | 3.1316979979189 | 1990 | 3.2937723588502 | 1989 | 3.5536926918087 | 1988 | 3.8678425322344 | 1987 | 4.3363810737852 | 1986 | 3.7460655834588 | 1985 | 4.5126541856097 | 1984 | 4.7763574295637 | 1983 | 4.891700363572 | 1982 | 5.3628248573767 | 1981 | 4.5701239334942 | 1980 | 4.2851265949173 | 1979 | 4.7034928856455 | 1978 | 5.3732603730816 | 1977 | 5.5721931130878 | 1976 | 4.4547019273246 | 1975 | 4.2910780205527 | 1974 | 3.5522174979543 | 1973 | 3.2013500579932 | 1972 | 3.4559053504655 | 1971 | 3.5566963187012 | 1970 | 3.4916089467284 | 1969 | 3.7331497025266 | 1968 | 3.6132637795836 | 1967 | 3.3534912414264 | 1966 | 3.3030513184168 | 1965 | 3.4345616351392 | 1964 | 3.1154222704764 | 1963 | 3.0764760478031 | 1962 | 2.6693406419495 | 1961 | 2.235409994517 | 1960 | 2.2496484239859 |
|