Year % 1990 47.3141773724755 1991 47.8043118861471 1992 48.325609670462 1993 48.903076138988 1994 49.3585833480609 1995 49.7913858916701 1996 50.1766837346081 1997 50.5401824549382 1998 50.8618686961386 1999 51.1527260712744 2000 51.4020331633427 2001 51.5989994720883 2002 51.7395534387016 2003 51.8458896483304 2004 51.916734043982 2005 51.9628229987055 2006 52.0138046110791 2007 52.0703526209951 2008 52.1348357824909 2009 52.2043887290035 2010 52.323087532113 2011 52.4345038154892 2012 52.5734865902593 2013 52.7426698318354 2014 52.9023289023524 2015 53.0610360426881 2016 53.2043791976964 2017 53.327970925241 2018 53.4251806863912 2019 53.4872412011353 2020 53.5227355385831 2021 53.5139597503201 2022 53.4466026722437