Add terms from USDA ERS

[ramonawalls]

Vulnerabilities:

Food insecurity:

Variable Name	Variable Code
Household food insecurity (%, three-year average), 2012-14*	FOODINSEC_12_14
Household food insecurity (%, three-year average), 2015-17*	FOODINSEC_15_17
Household food insecurity (change %),2012-14 to 2015-17*	CH_FOODINSEC_14_17
Household very low food security (%, three-year average), 2012-14*	VLFOODSEC_12_14
Household very low food security (%, three-year average), 2015-17*	VLFOODSEC_15_17
Household very low food security (change %), 2012-14 to 2015-17*	CH_VLFOODSEC_14_1

Data are at https://docs.google.com/spreadsheets/d/1GyF3h4NC8bQt2-EkdR_bt-H9YBgckAhX/edit#gid=737146962

De we need to use both time periods for the same variable? If so, should they be two different variables or have an annotation property for time? We have a lot of variables that have dates associated with them.

Resiliencies: