# year    value 
 1980     0.39 
 1981     0.65 
 1982    -0.45 
 1983     0.75 
 1984    -0.63 
 1985    -1.87 
 1986    -0.67 
 1987     0.45 
 1988     0.24 
 1989     0.14 
 1990     1.07 
 1991    -0.62 
 1992    -0.15 
 1993    -1.23 
 1994     0.42 
 1995     0.11 
 1996    -1.05 
 1997     0.51 
 1998     1.61 
 1999     1.09 
 2000    -0.45 
 2001     1.25 
 2002    -0.32 
 2003     0.32 
 2004     0.78 
 2005     1.33 
 2006    -0.22 
 2007     1.02 
 2008     0.53 
 2009     0.34 
 2010     0.67 
 2011     0.75 
 2012      0.7 
 2013     0.35 
 2014     0.42 
 2015     1.92 
 2016     2.34 
 2017     1.14 
 2018    -0.38