Whenever a department, commission, board, council, agency or public corporation incurs expenditures through contracts or agreements by which a nongovernmental person or entity agrees to provide services which are substantially similar to and in lieu of services hereto fore provided, in whole or in part, by regular employees of the department, commission, board, council, agency or public corporation covered by chapter 36-8, those expenditures shall be subject to an assessment equal to five and one-half percent (5.5%) of the cost of the service. That assessment shall be paid to the retirement system on a quarterly basis in accordance with subsection 36-10-2(e).