| Year | Value | | 2020 | 0.99434784276235 | | 2019 | 0.99529792821627 | | 2018 | 0.95203315917284 | | 2017 | 0.85702287394051 | | 2016 | 0.92612422798863 | | 2015 | 0.93487978030325 | | 2014 | 0.85272226020338 | | 2013 | 0.84599381468174 | | 2012 | 0.8415980703254 | | 2011 | 0.83685296711677 | | 2010 | 0.84359586036508 | | 2009 | 0.792708824231 | | 2008 | 1.0079338795375 | | 2007 | 1.0165523771351 | | 2006 | 1.0134601992463 | | 2005 | 1.1966696683131 | | 2004 | 0.8923259964307 | | 2003 | 1.2063516649142 | | 2002 | 1.2388768739925 | | 2001 | 1.0981704179968 | | 2000 | 1.1299955840962 | | 1999 | 1.1411668430971 | | 1998 | 1.0632626377848 | | 1997 | 0.92263216705793 | | 1996 | 0.79598130746442 | | 1995 | 0.78062461323599 | | 1994 | 0.54953509331106 | | 1993 | 0.67445527619618 | | 1992 | 0.38705931684031 |
|