Year % 1990 59.9921639689497 1991 60.456695954427 1992 60.5948671463373 1993 60.6261437684927 1994 60.6286067600989 1995 60.6064658681242 1996 60.5295677008824 1997 60.4244029352279 1998 60.3083019823154 1999 60.1906814031556 2000 60.075623044492 2001 59.9683469365202 2002 59.8953840148336 2003 59.7935392008543 2004 59.6789853521299 2005 59.5857378245593 2006 59.4664235166434 2007 59.3385530622209 2008 59.2254221863392 2009 59.1457032143575 2010 59.1054053229671 2011 59.1804674994117 2012 59.2631096758683 2013 59.3959924211977 2014 59.5430006513352 2015 59.6763425477256 2016 59.8054722297973 2017 59.9363727694589 2018 60.0744133647589 2019 60.2592271027872 2020 60.4788601207319 2021 60.7696341438124 2022 60.9951917369108