Figure 18	
"Trends in the Occurrence of MTBE in Drinking Water Derived from Ground Water in 6 Northeast States, 1993-2006"	

Title:	Detection frequency of MTBE in drinking water by principal aquifer for select one-well systems for all States and by year.

	
Description:	These are graphs of detection frequencies of MTBE in drinking water by principal aquifer for select one-well systems in all States by year.
	
	
	
Origin of data:	The data were obtained from the one-well data set on MTBE in drinking water and the data on MTBE in gasoline: 150.one.well.systems.selected.by.PA.rdb
	
	
	
Manipulation of data set:	"Initially, data was made unique by PWSID and SampleYear retaining any quantified concentrations of MTBE.  Then, detection frequencies of MTBE in drinking water for all systems in all States by year were computed from the one-well system data set on MTBE in drinking water for all States by year."
	
	
	
Other:	
