Year	Percent change (Units)
1980	4.601
1981	5.910
1982	5.353
1983	5.581
1984	5.760
1985	4.643
1986	5.534
1987	9.519
1988	13.288
1989	12.194
1990	11.623
1991	8.403
1992	9.230
1993	8.676
1994	7.997
1995	8.120
1996	5.652
1997	-2.754
1998	-7.634
1999	4.572
2000	4.455
2001	3.444
2002	6.149
2003	7.189
2004	6.289
2005	4.188
2006	4.968
2007	5.435
2008	1.726
2009	-0.691
2010	7.513
2011	0.840
2012	7.243
2013	2.687
2014	0.984
2015	3.134
2016	3.435
2017	4.178
2018	4.223
2019	2.115
2020	-6.050
2021	1.549
2022	2.511
2023	1.872
2024	2.700
2025	2.900
2026	3.004
2027	2.980
2028	2.969
2029	2.978