What years of data does RDAS have?
RDAS has data for 2010-2011 and 2012-2013, but not a combination of 2011-2012.
All our year pairs start with an even number. 2015-2016 is a special case because SAMHSA broke trends in 2015, so they wanted a file that would make the new survey questions available sooner. Otherwise, users would have to wait until the 2017 data was released.