Year | Value | 2021 | 16.374269005848 | 2020 | 16.233918128655 | 2019 | 16.140350877193 | 2018 | 15.976608187135 | 2017 | 15.883040935673 | 2016 | 16.011042097999 | 2015 | 15.527950310559 | 2014 | 15.044858523119 | 2013 | 14.676788589832 | 2012 | 14.637886293937 | 2011 | 14.918612880396 | 2010 | 15.215852795471 | 2009 | 14.069355980184 | 2008 | 14.102382637415 | 2007 | 14.13776834159 | 2006 | 13.189431469686 | 2005 | 13.960839820712 | 2004 | 12.250530785563 | 2003 | 12.856805850436 | 2002 | 14.47511205473 | 2001 | 15.970747817882 | 2000 | 19.886765746638 | 1999 | 20.264213257844 | 1998 | 20.924746402453 | 1997 | 20.948336871904 | 1996 | 20.853974994102 | 1995 | 20.618070299599 | 1994 | 22.387355508375 | 1993 | 25.147440434065 | 1992 | 26.303373437131 |
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