Year	Percent change (Units)
1981	6.585
1982	5.872
1983	-6.485
1984	-2.073
1985	4.634
1986	18.848
1987	27.402
1988	21.642
1989	8.496
1990	16.121
1991	8.363
1992	10.993
1993	-1.534
1994	10.565
1995	9.436
1996	5.152
1997	4.346
1998	21.276
1999	1.965
2000	-7.684
2001	3.074
2002	4.362
2003	10.961
2004	8.428
2005	-4.630
2006	4.872
2007	10.340
2008	2.194
2009	-15.739
2010	-4.515
2011	-4.685
2012	-11.852
2013	7.426
2014	8.998
2015	8.088
2016	5.027
2017	7.998
2018	5.055
2019	5.125
2020	-11.848
2021	12.151
2022	10.850
2023	2.247
2024	3.443
2025	2.921
2026	2.872
2027	2.648
2028	2.541
2029	2.731