| Year | Value | | 2021 | 1,435 | | 2020 | 3,166 | | 2019 | 8,310 | | 2018 | 7,777 | | 2017 | 5,277 | | 2016 | 6,009 | | 2015 | 5,219 | | 2014 | 5,705.561469737 | | 2013 | 4,212 | | 2012 | 9,611.0282613426 | | 2011 | 7,194.2584412287 | | 2010 | 6,528 | | 2009 | 4,783 | | 2008 | 5,592 | | 2007 | 6,158 | | 2006 | 6,169 | | 2005 | 5,332 | | 2004 | 6,702 | | 2003 | 7,358 | | 2002 | 6,264 | | 2001 | 5,947 | | 2000 | 6,200 | | 1999 | 2,200 | | 1998 | 4,900 | | 1997 | 4,900 | | 1996 | 10,500 | | 1995 | 10,500 | | 1994 | 10,000 | | 1993 | 10,000 | | 1992 | 17,900 | | 1991 | 9,800 |
|