Pension or Retirement System in Mobile County and Municipalities Therein.

The legislature may hereafter, by general, local, or special laws, provide for the establishment of a pension or retirement system or systems for the benefit of public officers of Mobile county and the officers of incorporated municipalities within the county, any provision of the Constitution to the contrary notwithstanding, and may provide for the retirement of such officers on pay or part pay. But any such law shall not become operative until it is first approved by a majority of the qualified electors of the county, or of the municipality affected thereby, voting in a referendum election held for that purpose.