# year    value 
 1980     0.48 
 1981     1.08 
 1982     0.12 
 1983     1.62 
 1984     0.21 
 1985     -0.9 
 1986     0.35 
 1987     0.89 
 1988     0.67 
 1989     1.28 
 1990     1.33 
 1991     0.78 
 1992     1.33 
 1993     0.84 
 1994      0.1 
 1995     1.74 
 1996    -0.02 
 1997     1.12 
 1998     1.65 
 1999     1.98 
 2000     1.86 
 2001     0.78 
 2002     2.38 
 2003     0.31 
 2004     1.76 
 2005     0.73 
 2006     0.65 
 2007     2.52 
 2008     0.57 
 2009     0.88 
 2010      0.4 
 2011     0.45 
 2012      0.6 
 2013     0.82 
 2014     0.83 
 2015     1.72 
 2016     3.02 
 2017     1.92 
 2018     1.09