Minn. Stat. § 353.63
It is the recognized policy of the state that special consideration should be given to employees of governmental subdivisions who devote their time and skills to protecting the property and personal safety of others. Since this work is hazardous, special provisions are hereby made for retirement pensions, disability benefits and survivors benefits based on the particular dangers inherent in these occupations. The benefits provided in sections 353.63 to 353.68 are more costly than similar benefits for other public employees since they are computed on the basis of a shorter working lifetime taking into account experience which has been universally recognized. This extra cost should be borne by the employee and employer alike at the ratio of 40 percent employee contributions and 60 percent employer contributions.
Minn. Stat. § 353.63
1959 c 650 s 31