Year % 1990 21.4250124564026 1991 22.1729490022173 1992 22.8571428571429 1993 23.5031610264039 1994 24.0559440559441 1995 24.5989304812834 1996 25.0405449237755 1997 25.3410124280085 1998 25.529511437447 1999 25.7029177718833 2000 25.8218318695107 2001 25.9020310633214 2002 25.9835315645014 2003 26.0611392126677 2004 26.1146496815287 2005 26.1620732208968 2006 26.1790567545963 2007 26.1765849863866 2008 26.1395876678646 2009 26.0741828865222 2010 26.0024950989128 2011 25.9432329525788 2012 25.8791855965001 2013 25.8318308474021 2014 25.776 2015 25.7317264047582 2016 25.713847098557 2017 25.7095410628019 2018 25.7147111375819 2019 25.7290132547865 2020 25.7414170927684 2021 25.7853403141361 2022 25.8307937890002