# year    value 
 1980     0.52 
 1981     0.26 
 1982        0 
 1983     0.34 
 1984     0.36 
 1985     0.21 
 1986     0.19 
 1987      0.4 
 1988     0.67 
 1989     0.09 
 1990      0.2 
 1991     0.49 
 1992     0.16 
 1993     0.17 
 1994     0.42 
 1995     0.46 
 1996     0.39 
 1997     0.16 
 1998     1.11 
 1999     0.65 
 2000      0.6 
 2001     0.72 
 2002     0.96 
 2003     0.87 
 2004     0.88 
 2005     0.88 
 2006     0.73 
 2007     0.79 
 2008     0.75 
 2009     0.83 
 2010     1.45 
 2011     0.67 
 2012     0.78 
 2013     0.96 
 2014     0.92 
 2015     0.99 
 2016     1.54 
 2017      1.1 
 2018     1.15