Year Index 1980 17.22 1981 16.757 1982 17.29 1983 18.876 1984 18.876 1985 18.876 1986 18.876 1987 18.876 1988 24.339 1989 23.723 1990 24.701 1991 26.428 1992 27.193 1993 26.514 1994 28.436 1995 32.989 1996 33.944 1997 37.763 1998 39.763 1999 44.164 2000 49.93 2001 53.342 2002 59.715 2003 63.804 2004 64.485 2005 69.587 2006 76.149 2007 76.412 2008 85.327 2009 81.16 2010 89.212 2011 97.092 2012 96.544 2013 100 2014 103.05 2015 98.513 2016 101.057 2017 108.435 2018 116.931 2019 116.528 2020 119.592 2021 122.716 2022 126.053 2023 128.736 2024 131.035