Year	Percent change (Units)
1991	70.514
1992	-8.354
1993	-0.496
1994	-3.337
1995	15.927
1996	-25.973
1997	57.185
1998	14.683
1999	-15.753
2000	-15.903
2001	37.583
2002	-2.936
2003	36.252
2004	-21.096
2005	42.364
2006	-25.361
2007	18.309
2008	14.124
2009	-0.941
2010	36.550
2011	9.241
2012	-14.131
2013	-1.259
2014	17.597
2015	19.332
2016	-25.487
2017	-16.419
2018	8.014
2019	60.427
2020	0.295
2021	-27.971
2022	-9.173
2023	11.117
2024	0.448
2025	-3.635
2026	-1.383
2027	2.218
2028	-0.550
2029	0.529