# year    value 
 1980     0.32 
 1981     0.26 
 1982      0.3 
 1983     0.63 
 1984     0.15 
 1985      0.1 
 1986     0.24 
 1987     0.86 
 1988     0.38 
 1989     0.33 
 1990      0.4 
 1991     0.41 
 1992     0.32 
 1993     0.52 
 1994     0.28 
 1995     0.66 
 1996     0.45 
 1997     0.65 
 1998     1.05 
 1999     0.41 
 2000     0.46 
 2001     0.62 
 2002     0.86 
 2003     0.68 
 2004     0.61 
 2005     0.81 
 2006     0.79 
 2007     0.64 
 2008      0.5 
 2009     1.08 
 2010     0.89 
 2011     0.92 
 2012     0.79 
 2013     0.69 
 2014     1.03 
 2015     1.16 
 2016     1.13 
 2017     1.08 
 2018     0.93