| Year | Value | | 2021 | 63.07134829725 | | 2020 | 59.569138435789 | | 2019 | 53.748884366603 | | 2018 | 49.157563210755 | | 2017 | 45.543073180762 | | 2016 | 43.215980241478 | | 2015 | 40.270058639491 | | 2014 | 37.880780966035 | | 2013 | 35.649257518672 | | 2012 | 33.71336142704 | | 2011 | 31.211965092394 | | 2010 | 28.797653077536 | | 2009 | 25.560005264161 | | 2008 | 23.006835501859 | | 2007 | 20.354536845585 | | 2006 | 17.426420715017 | | 2005 | 15.674661470169 | | 2004 | 14.081818572061 | | 2003 | 12.195854587379 | | 2002 | 10.518528420417 | | 2001 | 8.053555972904 | | 2000 | 6.7437195116479 | | 1999 | 4.6329027842565 | | 1998 | 3.1405795977232 | | 1997 | 2.04269705765 | | 1996 | 1.326567157771 | | 1995 | 0.6830820605321 | | 1994 | 0.36050814899943 | | 1993 | 0.17900667956123 | | 1992 | 0.12518632906822 | | 1991 | 0.078810516480602 | | 1990 | 0.048824693083671 |
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