Year % 1997 42.14619 1998 2.120507 1999 4.290927 2000 4.96614 2001 4.764191 2002 4.726994 2003 5.89894 2004 6.743919 2005 6.791521 2006 7.566948 2007 52.63393 2008 50.23869 2009 8.004948 2010 7.228723 2011 7.041047 2012 7.923475 2013 34.31874 2015 5.91623 2020 11.2766 2021 10.03894