Year	Percent change (Units)
1993	10.619
1994	7.289
1995	12.302
1996	3.509
1997	7.736
1998	9.020
1999	10.625
2000	26.835
2001	7.749
2002	23.818
2003	20.848
2004	17.383
2005	18.500
2006	8.752
2007	14.886
2008	36.511
2009	18.965
2010	4.694
2011	7.708
2012	6.607
2013	9.935
2014	1.342
2015	50.830
2016	-22.041
2017	-18.164
2018	-29.277
2019	5.600