Year Index 1980 23.322 1981 25.054 1982 27.334 1983 30.475 1984 34.257 1985 37.507 1986 41.075 1987 44.811 1988 48.432 1989 52.022 1990 55.368 1991 57.976 1992 58.892 1993 60.109 1994 63.5 1995 67.116 1996 69.561 1997 72.502 1998 76.087 1999 78.519 2000 79.865 2001 81.791 2002 84.977 2003 88.705 2004 92.852 2005 97.62 2006 103.346 2007 110.778 2008 118.821 2009 127.108 2010 136.693 2011 147.661 2012 158.922 2013 169.052 2014 178.829 2015 190.158 2016 202.501 2017 214.496 2018 226.49 2019 239.161 2020 252.456 2021 266.352 2022 280.997 2023 296.452 2024 312.757