# year    value 
 1980 1.488119 
 1981 1.538713 
 1982 1.508672 
 1983 1.270505 
 1984 1.403784 
 1985 1.388627 
 1986 1.389571 
 1987 1.518976 
 1988 1.637407 
 1989 1.548418 
 1990  1.67858 
 1991 1.676716 
 1992 1.333988 
 1993 1.440951 
 1994 1.397297 
 1995  1.47872 
 1996 1.651652 
 1997 1.700151 
 1998 1.732127 
 1999 1.761506 
 2000 1.837583 
 2001 1.840481 
 2002  1.99447 
 2003 1.925062 
 2004 1.861357 
 2005 2.015064