Year	Percent change (Units)
1991	-5.000
1992	8.400
1993	-12.900
1994	-8.700
1995	17.140
1996	2.710
1997	3.606
1998	-0.653
1999	-4.704
2000	12.138
2001	-3.380
2002	-9.556
2003	8.139
2004	17.265
2005	14.516
2006	6.682
2007	16.627
2008	1.465
2009	0.221
2010	12.698
2011	10.978
2012	15.321
2013	35.178
2014	8.971
2015	-11.545
2016	14.750
2017	0.669
2018	11.401
2019	-1.342
2020	-0.640
2021	4.955
2022	5.451
2023	3.980
2024	3.424
2025	4.064
2026	4.171
2027	5.231
2028	3.967
2029	2.972