Year | Value | 2022 | 51.300527591423 | 2021 | 51.349533706036 | 2020 | 51.394817384131 | 2019 | 51.438495203449 | 2018 | 51.477980283621 | 2017 | 51.510094002407 | 2016 | 51.405421908376 | 2015 | 51.401009268583 | 2014 | 51.5788353535 | 2013 | 51.671851765064 | 2012 | 51.733231589112 | 2011 | 51.797663477669 | 2010 | 51.863387027278 | 2009 | 51.92585596557 | 2008 | 51.987148945616 | 2007 | 52.052040305389 | 2006 | 52.120823920655 | 2005 | 52.193682345486 | 2004 | 52.268415622014 | 2003 | 52.342091875511 | 2002 | 52.410701850554 | 2001 | 52.471010093349 | 2000 | 52.531880599828 | 1999 | 52.599635054105 | 1998 | 52.666390939961 | 1997 | 52.73116857467 | 1996 | 52.634597553518 | 1995 | 52.346364818473 | 1994 | 52.054186395844 | 1993 | 51.748005429221 | 1992 | 51.416596754537 | 1991 | 51.262777780399 | 1990 | 51.294396825082 | 1989 | 51.355631859621 | 1988 | 51.429156016632 | 1987 | 51.507659346866 | 1986 | 51.588837196713 | 1985 | 51.086870474546 | 1984 | 50.144083257287 | 1983 | 49.393924577727 | 1982 | 48.77224427742 | 1981 | 48.295544661268 | 1980 | 48.148934807548 | 1979 | 48.305262700851 | 1978 | 48.487314287841 | 1977 | 48.697591507714 | 1976 | 48.835190688927 | 1975 | 48.919026343586 | 1974 | 49.040731161953 | 1973 | 49.1798117774 | 1972 | 49.328706656499 | 1971 | 49.463987077491 | 1970 | 49.492728684953 | 1969 | 49.418039280298 | 1968 | 49.334924424742 | 1967 | 49.244971149169 | 1966 | 49.15155410338 | 1965 | 49.054880041344 | 1964 | 48.95431120958 | 1963 | 48.851474167667 | 1962 | 48.745690271564 | 1961 | 48.640410315475 | 1960 | 48.53369229066 |
|