Table 3.

Sampling for the field survey, by year.

Years	Samples
2003	6
2004	68
2005	55
2006	73
2007	62
2008	22
2009	17
2010	27
2011	11
2012	54
2013	36
2014	21
2015	36
2016	38
2017	57
2018	52
2019	103