Year	Percent change (Units)
1991	8.410
1992	8.076
1993	11.700
1994	-44.317
1995	36.429
1996	48.517
1997	15.126
1998	15.924
1999	-15.121
2000	-7.414
2001	12.630
2002	13.859
2003	-1.857
2004	-10.271
2005	1.835
2006	12.736
2007	8.053
2008	9.318
2009	-2.124
2010	-6.359
2011	-14.336
2012	22.260
2013	-2.659
2014	4.150
2015	-7.772
2016	-5.239
2017	0.839
2018	5.800
2019	17.282
2020	10.661
2021	-5.755
2022	-8.129
2023	-4.102
2024	5.066
2025	0.679
2026	6.125
2027	5.636
2028	5.143
2029	4.648