Year	US Dollars
1997	17.05
1998	17.72
1999	18.54
2000	20.12
2001	21.45
2002	22.48
2003	23.04
2004	24.15
2005	21.23
2006	22.31
2007	22.52
2009	22.97
2010	23.62
2011	23.38
2012	28.93
2013	29.49
2014	29.78
2015	30.83
2016	31.21