Year	Percent change (Units)
1997	-22.996
1998	66.949
1999	59.463
2000	-1.310
2001	-22.968
2002	41.015
2003	110.310
2004	-2.083
2005	-0.906
2006	-3.798
2007	53.328
2008	11.152
2009	-5.900
2010	42.949
2011	0.249
2012	-14.459
2013	20.358
2014	12.779
2015	-19.282
2016	16.938
2017	-0.705
2018	14.176
2019	-17.016
2020	48.438
2021	32.653
2022	25.548
2023	4.743
2024	2.507
2025	4.826
2026	3.518
2027	3.363
2028	2.848
2029	2.537