Year	Percent change (Units)
1993	4.787
1994	13.147
1995	11.983
1996	10.288
1997	3.739
1998	9.467
1999	8.397
2000	19.947
2001	14.625
2002	16.877
2003	22.669
2004	25.111
2005	12.506
2006	7.707
2007	9.409
2008	22.168
2009	33.852
2010	10.297
2011	5.887
2012	6.035
2013	6.274
2014	8.360
2015	28.483
2016	-5.577
2017	-13.306
2018	-14.401
2019	1.300