Year Index (Units) 1987 1.003 1988 1.314 1989 2.483 1990 6.233 1991 15.582 1992 33.034 1993 46.578 1994 60.505 1995 59.380 1996 65.338 1997 76.243 1998 82.329 1999 82.478 2000 82.760 2001 82.324 2002 83.499 2003 83.464 2004 87.858 2005 95.248 2006 99.249 2007 113.096 2008 127.256 2009 134.032 2010 138.245 2011 145.030 2012 148.715 2013 155.668 2014 157.287 2015 161.766 2016 168.034 2017 171.782 2018 174.586 2019 179.950 2020 185.125 2021 191.979 2022 197.500 2023 202.840 2024 208.798 2025 215.144 2026 221.684 2027 228.334 2028 235.184 2029 242.240