Year	Percent change (Units)
1988	14.800
1989	75.871
1990	29.188
1991	10.360
1992	6.003
1993	10.315
1994	5.691
1995	28.750
1996	12.760
1997	8.726
1998	141.884
1999	86.656
2000	10.560
2001	7.523
2002	15.189
2003	12.624
2004	8.663
2005	8.780
2006	4.546
2007	5.745
2008	3.174
2009	3.926
2010	5.758
2011	7.696
2012	4.733
2013	6.650
2014	2.399
2015	0.897
2016	2.487
2017	0.148
2018	1.485
2019	6.284
2020	3.226
2021	5.268
2022	39.266
2023	24.369
2024	18.500
2025	11.000
2026	3.000
2027	3.000
2028	3.000
2029	3.000