The Mexican health system is characterised by fragmentation with several public purchasers vertically integrated with providers [19].
Social security services are available for the formally employed and their families. The largest is the Mexican Institute of Social Security
(IMSS) [23]. IMSS is available for the employees of private enterprises and their families, and in 2012, it covered approximately 30% of the
population [24]. An additional 7% are covered by other social security institutions, like ISSSTE (for employees of the State), PEMEX (for
employees of the Mexican Oil Company), SEMAR (for Marines), SEDENA (for the military), and others [24]. For workers in the informal
sector (self-employed persons or wage earners who do not make social security contributions) Seguro Popular (SP) provides cover through
government sponsored facilities run by the Ministry of Health (MOH).