Year	Percent change (Units)
1980	5.149
1981	3.423
1982	3.619
1983	1.875
1984	-7.324
1985	-7.307
1986	3.417
1987	4.312
1988	6.753
1989	6.205
1990	3.037
1991	-0.436
1992	0.418
1993	2.182
1994	4.374
1995	4.625
1996	5.860
1997	5.186
1998	-0.514
1999	3.346
2000	4.383
2001	3.049
2002	3.716
2003	5.087
2004	6.569
2005	4.942
2006	5.316
2007	6.519
2008	4.344
2009	1.448
2010	7.335
2011	3.858
2012	6.897
2013	6.751
2014	6.348
2015	6.348
2016	7.149
2017	6.931
2018	6.341
2019	6.119
2020	-9.518
2021	5.715
2022	7.570
2023	5.568
2024	6.163
2025	6.177
2026	6.187
2027	6.316
2028	6.324
2029	6.398