# year    value 
 1980     0.35 
 1981      0.6 
 1982     -0.7 
 1983     0.64 
 1984    -0.78 
 1985    -1.98 
 1986    -0.72 
 1987     0.64 
 1988     0.53 
 1989     0.23 
 1990     1.04 
 1991     -0.2 
 1992    -0.03 
 1993       -1 
 1994     0.02 
 1995     0.57 
 1996    -0.71 
 1997     0.55 
 1998     1.32 
 1999     1.18 
 2000    -0.67 
 2001     1.41 
 2002    -0.19 
 2003     0.56 
 2004     0.44 
 2005     1.05 
 2006    -0.12 
 2007     0.89 
 2008     0.76 
 2009     0.38 
 2010     0.65 
 2011     0.76 
 2012     1.06 
 2013     0.33 
 2014     0.86 
 2015      1.7 
 2016     2.07 
 2017     1.17 
 2018    -0.06