Year | Value | 2021 | 19.302121422078 | 2020 | 18.637668665552 | 2019 | 18.78383560839 | 2018 | 18.546740404443 | 2017 | 18.565870835031 | 2016 | 18.091773037848 | 2015 | 18.107897945996 | 2014 | 17.435784158644 | 2013 | 16.692724892192 | 2012 | 15.516106292831 | 2011 | 15.969448907797 | 2010 | 15.003580239799 | 2009 | 15.523308267463 | 2008 | 16.445808688412 | 2007 | 16.748900533335 | 2006 | 16.800847388085 | 2005 | 18.007109899555 | 2004 | 17.292876122586 | 2003 | 17.683024997072 | 2002 | 17.118246962858 | 2001 | 17.275381306523 | 2000 | 18.501773803138 | 1999 | 19.745856584764 | 1998 | 20.162761338039 | 1997 | 20.462120898944 | 1996 | 21.418577910969 | 1995 | 23.241738851719 |
|