# year    value 
 1980    -0.01 
 1981     0.45 
 1982    -0.13 
 1983     0.41 
 1984     0.26 
 1985    -0.11 
 1986        0 
 1987     0.13 
 1988     0.75 
 1989     0.48 
 1990     0.46 
 1991     0.58 
 1992    -0.47 
 1993    -0.12 
 1994     0.61 
 1995      0.8 
 1996     0.38 
 1997     0.56 
 1998      1.1 
 1999     0.96 
 2000     0.72 
 2001     0.92 
 2002     0.78 
 2003     0.89 
 2004     0.43 
 2005     0.99 
 2006     1.21 
 2007     1.07 
 2008     0.97 
 2009     0.51 
 2010     1.64 
 2011     1.18 
 2012     1.57 
 2013        1 
 2014     0.95 
 2015     1.13 
 2016     1.48 
 2017     1.19 
 2018     1.39