An insurer may invest in bonds, notes or evidences of indebtedness issued by any local improvement district in this or any other state to finance local improvements authorized by law, if the principal and interest of such obligations is payable from assessments on real property within such local improvement district. No such investment shall be made unless the face value of all such obligations, and similar obligations outstanding do not exceed fifty per cent of the market value of the real property and improvements upon which the bonds or the assessments for the payment of principal and interest thereon are liens inferior only to the liens for general ad valorem property taxes. No such investment shall be made unless no default in payment of principal or interest on the obligations to be purchased has occurred within five years of the date of investment therein, or if such obligations were issued less than five years prior to the date of investment, no default in payment of principal or interest has occurred on the obligations to be purchased or on any other obligation of the issuer within five years of such investment.