# year    value 
 1979 -3.505977 
 1980 0.2990833 
 1981 1.568767 
 1982 -0.7174089 
 1983  0.11819 
 1984 -1.297491 
 1985 -2.773785 
 1986 0.4014707 
 1987 -0.8389501 
 1988 -1.29405 
 1989 -2.390471 
 1990 -0.7108499 
 1991 -1.304258 
 1992 0.1636405 
 1993 -2.423045 
 1994 -0.3600805 
 1995 0.7172748 
 1996 0.2796729 
 1997 -0.5047719 
 1998 -0.5967922 
 1999 0.1254352 
 2000 0.8423867 
 2001 -1.341237 
 2002 -1.06588 
 2003 0.887024 
 2004 -0.7603297 
 2005 0.4102754 
 2006 0.268404 
 2007 -0.8786959 
 2008 -1.412525 
 2009 -0.3157443 
 2010 -1.163982 
 2011 -0.6529408 
 2012 -0.02636088 
 2013 -1.36071 
 2014 -0.138062 
 2015 2.189557 
 2016 0.4031633 
 2017 -0.7181814 
 2018 0.9098371 
 2019 -0.9491448