Year % 1990 25.0368188512518 1991 25.0327653997379 1992 24.9106078665078 1993 24.9173098125689 1994 24.7678018575851 1995 24.6588693957115 1996 24.582560296846 1997 24.3794326241135 1998 24.190800681431 1999 23.9837398373984 2000 23.9164086687307 2001 23.7075332348597 2002 23.4961075725407 2003 23.3174711080897 2004 23.1372549019608 2005 23.0188679245283 2006 22.8952150211993 2007 22.6557949912638 2008 22.2905027932961 2009 22.0031965903037 2010 21.7501264542236 2011 21.4697406340058 2012 21.1678832116788 2013 20.8981001727116 2014 20.5170291341814 2015 20.0779727095517 2016 19.6296296296296 2017 19.1496837666901 2018 18.6582109479306 2019 18.18759936407 2020 17.8169656430526 2021 17.4686497521143 2022 17.3125174240312