 
<prompt> De jure mean household size for the survey years 1990, 1997, 2002, 2007, 2009, and 2012, with 95% confidence intervals | (1990.0, 6.9) (1997.0, 6.0) (2002.0, 5.7) (2007.0, 5.3) (2009.0, 5.1) (2012.0, 5.1) <response> Figure 2 shows that the mean de jure (or usual resident) household size significantly decreased from 6.9 in 1990 to 5.1 in 2009, but remained unchanged between 2009 and 2012  