# year    value 
 1979  -2.1426 
 1980 -0.505307 
 1981 -3.18678 
 1982 -1.569908 
 1983 -0.9252005 
 1984 -1.682668 
 1985 -3.019426 
 1986 -1.932951 
 1987 -2.256555 
 1988 0.4572372 
 1989 0.1965304 
 1990 0.7931017 
 1991 -2.506514 
 1992 -1.492092 
 1993 -0.8002389 
 1994 0.2182256 
 1995 0.4973242 
 1996 -1.30405 
 1997 -0.1931304 
 1998 0.8652254 
 1999 -1.534771 
 2000 -0.899326 
 2001 0.8770478 
 2002 -0.8123093 
 2003 -1.481455 
 2004 -0.6281568 
 2005 -1.64681 
 2006 -2.20517 
 2007  2.23142 
 2008 0.7433828 
 2009 -1.162615 
 2010 -1.428644 
 2011 -0.8090144 
 2012 -1.225653 
 2013 -0.9712475 
 2014 1.856185 
 2015 0.6383914 
 2016 2.032714 
 2017 -0.3394755 
 2018 -0.1001989