# year    value 
 1980    -1.27 
 1981     1.11 
 1982    -0.19 
 1983     0.78 
 1984    -1.11 
 1985     0.14 
 1986     0.63 
 1987     -1.4 
 1988     0.46 
 1989     1.49 
 1990     1.41 
 1991    -0.24 
 1992     1.06 
 1993     0.96 
 1994     1.39 
 1995     0.09 
 1996    -0.09 
 1997     0.58 
 1998     0.87 
 1999     1.54 
 2000     2.05 
 2001     1.68 
 2002     1.59 
 2003      1.6 
 2004      0.2 
 2005     0.66 
 2006     0.49 
 2007     2.71 
 2008     1.12 
 2009      2.1 
 2010     0.56 
 2011     2.16 
 2012     1.84 
 2013     0.19 
 2014     1.89 
 2015     1.42 
 2016     1.16 
 2017     2.07 
 2018     2.36