Growth of managed care in California

The number and characteristics of people in California who have been certified eligible for Medi-Cal is changing dramatically over the last several years. Here's some data I extracted from the following dataset: Statewide Medi-Cal Certified Eligible Individuals, by Aid Code, 2013 - 2015.



Where M1 (the light blue line) = "Adult 19 to 64 at or below 138% FPL Citiz/Lawful" and 3N = "AFDC-MN-1931(b) Non CalWORKS" (more info here: http://healthconsumer.org/cs0151931b.pdf). It would be interesting to dig deeper to understand the basis of this change (is this a true change, or just a change in definitions?).