year,price
1984,1.198
1985,1.196
1986,0.931
1987,0.957
1988,0.964
1989,1.06
1990,1.217
1991,1.196
1992,1.19
1993,1.173
1994,1.174
1995,1.205
1996,1.288
1997,1.291
1998,1.115
1999,1.221
2000,1.563
2001,1.531
2002,1.441
2003,1.638
2004,1.923
2005,2.338
2006,2.635
2007,2.849
2008,3.317
2009,2.401
2010,2.836
2011,3.577
2012,3.695
2013,3.584
2014,3.425
2015,2.51