Year Percent 1971-01-01 88.7705104053569 1972-01-01 94.2812794586513 1973-01-01 101.8161406897770 1974-01-01 62.5965323854164 1975-01-01 71.4837769363714 1976-01-01 81.4493106467843 1977-01-01 102.9543834979160 1978-01-01 92.8280791505439 1979-01-01 85.2605270771059 1980-01-01 87.7901344129233 1981-01-01 105.7229033283720 1982-01-01 104.0580462604010 1983-01-01 142.5156252907890 1984-01-01 194.1817339211760 1985-01-01 195.6314872417290 1986-01-01 167.5964434191010 1987-01-01 173.2430764545670 1988-01-01 233.4033388206340 1989-01-01 191.8114126493140 1990-01-01 155.8248830318530 1991-01-01 153.5520008722630 1992-01-01 175.0752241658750 1993-01-01 155.9181680472720 1994-01-01 138.3068320973700 1995-01-01 93.5236678212102 1996-01-01 90.8436132110248 1997-01-01 91.3543935921138 1998-01-01 89.2186451657516 1999-01-01 97.5433481117374 2000-01-01 98.7287896691960 2001-01-01 105.4820657672170 2002-01-01 127.6441026398090 2003-01-01 151.2378572255420 2004-01-01 153.2624690989740 2005-01-01 161.6623006400770 2006-01-01 151.0075728851020 2007-01-01 134.1346650245210 2008-01-01 113.9859183660460 2009-01-01 120.6813705397090 2010-01-01 110.7907401596310 2011-01-01 112.8419567268870 2012-01-01 108.4944698751490 2013-01-01 101.2229669286730 2014-01-01 98.1765286376953 2015-01-01 113.1322546543850 2016-01-01 134.5558282237800 2017-01-01 144.8240286615080