§ 6. Defense; insurance fund. An employer who shall have contributed
to an insurance fund created and maintained for the mutual purpose of
indemnifying an employee for personal injuries, for which compensation
may be recovered under this article, or to any relief society or benefit
fund created under the laws of this state, may prove in mitigation of
damages recoverable by an employee under this article such proportion of
the pecuniary benefit which has been received by such employee from such
fund or society on account of such contribution of the employer, as the
contribution of such employer to such fund or society bears to the whole
contribution thereto.