# year    value 
 1980     1.06 
 1981     2.42 
 1982    -0.48 
 1983      1.6 
 1984    -0.71 
 1985    -1.41 
 1986     0.99 
 1987     1.43 
 1988    -0.03 
 1989    -0.71 
 1990     0.65 
 1991     0.08 
 1992     2.28 
 1993    -1.35 
 1994     0.21 
 1995     2.03 
 1996     0.91 
 1997     0.26 
 1998      1.7 
 1999     1.91 
 2000     2.55 
 2001    -0.46 
 2002     1.27 
 2003     1.64 
 2004     0.65 
 2005     1.76 
 2006     1.89 
 2007     0.29 
 2008     -0.2 
 2009     0.54 
 2010     -0.7 
 2011    -0.02 
 2012     1.66 
 2013     0.45 
 2014    -0.06 
 2015     2.28 
 2016     2.22 
 2017     0.94 
 2018     0.99