# year    value 
 1980    -0.32 
 1981     0.15 
 1982     1.36 
 1983    -0.11 
 1984     0.38 
 1985    -0.17 
 1986     0.43 
 1987     1.49 
 1988     -0.4 
 1989    -0.21 
 1990     0.46 
 1991     0.33 
 1992     0.44 
 1993    -0.64 
 1994     1.11 
 1995    -0.03 
 1996    -0.42 
 1997     0.49 
 1998    -0.54 
 1999     0.81 
 2000     1.56 
 2001     0.15 
 2002     0.78 
 2003     0.25 
 2004     1.02 
 2005     0.65 
 2006     2.24 
 2007    -0.66 
 2008     0.46 
 2009     1.34 
 2010     0.07 
 2011     1.28 
 2012     1.42 
 2013     1.15 
 2014     2.16 
 2015     0.96 
 2016     1.02 
 2017     0.37 
 2018     2.04