Year % 1981 20.2886150217863 1982 8.81974633960747 1983 13.2162359217677 1984 11.1460070912632 1985 9.93217252844568 1986 7.86341372820419 1987 20.8791419509691 1988 10.8570702396143 1989 16.6417776219273 1990 22.3770853618819 1991 18.8366959796337 1992 20.8589892380581 1993 6.595629423062239 1994 6.489801574255461 1995 28.1299488420923 1996 8.3767307992486 1997 45.6850352637463 1998 27.7851953450257 1999 30.060005908172897 2000 46.4064454854674 2001 17.6775511408186 2002 20.4553954359008 2003 28.4253567160114 2004 29.837137524770302 2005 24.731397292473602 2006 29.3510254863616 2007 47.5392346515386 2008 43.5011961844482 2009 27.9506294512273 2010 28.0871925340219 2011 32.9397532231502 2012 26.5024612635952 2013 28.410832718593 2014 31.0784470309074 2015 29.109262927648498 2016 27.0075052374268 2017 30.055717954107802 2018 34.0022 2019 26.889 2020 56.9499 2021 49.333 2022 28.975