Year	Percent change (Units)
1980	-7.441
1981	2.048
1982	-2.525
1983	13.582
1984	24.190
1985	6.255
1986	10.228
1987	4.670
1988	4.049
1989	4.303
1990	2.911
1991	0.455
1992	9.430
1993	10.001
1994	13.356
1995	9.013
1996	9.371
1997	14.408
1998	11.849
1999	12.812
2000	13.062
2001	-3.276
2002	3.718
2003	6.097
2004	11.212
2005	7.024
2006	6.075
2007	1.930
2008	-3.271
2009	-15.471
2010	15.376
2011	5.515
2012	2.652
2013	2.008
2014	5.565
2015	5.787
2016	1.107
2017	4.476
2018	5.133
2019	0.554
2020	-5.880
2021	14.582
2022	6.823
2023	-1.682
2024	0.512
2025	1.486
2026	2.276
2027	2.396
2028	2.243
2029	2.075