Year % 1990 5.56389472630842 1991 6.14530676974923 1992 6.78963110667996 1993 7.48402798904776 1994 8.21818181818182 1995 8.97435897435897 1996 9.66722830665543 1997 10.1809045226131 1998 10.587899543379 1999 10.9066427289049 2000 11.1703478040112 2001 11.3782051282051 2002 11.5643175466425 2003 11.7298916143754 2004 11.8832569425721 2005 12.0196290867376 2006 12.1275955461932 2007 12.1815469359651 2008 12.2178391409161 2009 12.2320633090509 2010 12.2272932443954 2011 12.1968787515006 2012 12.169384678635 2013 12.1031398000351 2014 12.0261437908497 2015 11.966537342386 2016 11.8879205908789 2017 11.9249530956848 2018 12.013763129301 2019 12.1307905735258 2020 12.3212019346208 2021 12.4546225614928 2022 12.4978922874583