insurance_plan_type choices (filtered for primary/secondary/tertiary insurance):

Value	Description
11	Other Non-Federal Programs
12	Preferred Provider Organization (PPO)
13	Point of Service (POS)
14	Exclusive Provider Organization (EPO)
16	Health Maintenance Organization (HMO) Medicare Risk
BL	Blue Cross/Blue Shield
CH	Champus
CI	Commercial Insurance Co.
FI	Federal Employees Program
HM	Health Maintenance Organization
LM	Liability Medical
MA	Medicare Part A (Institutional)
MB	Medicare Part B (Professional)
MC	Medicaid
OF	Other Federal Program
VA	Veterans Affairs Plan