# year    value 
 1980 0.9678006 
 1981 2.319925 
 1982 -0.8326355 
 1983 1.975158 
 1984 -0.749252 
 1985 -1.273566 
 1986 0.8632043 
 1987 2.078826 
 1988 0.05987906 
 1989 -0.2526015 
 1990 0.8956905 
 1991 0.4013211 
 1992 2.899571 
 1993 -1.257124 
 1994 -0.1195889 
 1995  2.07096 
 1996 0.3831074 
 1997 -0.2372047 
 1998 2.026232 
 1999 2.076886 
 2000 2.860074 
 2001 -1.027039 
 2002 1.745643 
 2003 1.152459 
 2004 0.7570487 
 2005 1.811195 
 2006 2.501962 
 2007 0.5828626 
 2008 0.1822363 
 2009 0.6155462 
 2010 -1.107545 
 2011 -0.2870135 
 2012 2.289023 
 2013 1.081778 
 2014 -0.7478817 
 2015 1.719161 
 2016 2.838202 
 2017 1.562075 
 2018 0.5751643