Annual Study

Sample Retention

Wave Participants(households) Preliminary Sample Retention Sample Retention
Wave 9 (2016) 1,525 70.9% 95.4%
Wave 8 (2015) 1,598 74.3% 98.6%
Wave 7 (2014) 1,620 75.3% 97.5%
Wave 6 (2013) 1,662 77.3% 97.6%
Wave 5 (2012) 1,703 79.2% 97.1%
Wave 4(2011) 1,754 81.6% 97.3%
Wave 3 (2010) 1,802 83.8% 94.6%
Wave 2 (2009) 1,904 88.6% 91.6%
Wave 1 (2008) 2,078 96.7% -
Preliminary (2008) 2,562 - -

* Notes: Among non-participating, pilot sample households, 52 and 20 households newly joined in the second year and third year study, respectively.