Year	Hours Per Week
1977	41.6
1978	41.1
1979	40
1980	39.7
1981	39.1
1982	39.1
1983	38.4
1984	37.6
1985	38.2
1992	38.7952
1993	39.4768
1994	39.0698
1995	38.5218
1996	38.181
1997	38.5126
1998	38.6926
1999	39.7894
2000	38.6865
2001	38.5865
2002	38.7123
2003	37.9371
2004	38.5818
2005	38.988
2006	38.8911
2007	38.7771
2008	38.6474
2009	38.1481
2010	38.0033
2011	37.8385
2012	37.4632
2013	37.457
2014	37.3644
2015	37.2944
2016	37.2788
2017	37.0994