The county treasurer of every county in this state may purchase an insurance policy providing indemnity for, or protection to, said county treasurer against his liability for the loss, without fault, connivance, or neglect on his part of money, securities, or other property for which he is accountable, including, but not limited to, loss caused by robbery or burglary. The principal amount of such insurance shall not exceed an amount equal to the greatest amount of cash which was in the hands of the county treasurer at any one time during the calendar year immediately preceding the year in which such insurance policy is purchased, unless the board of county commissioners shall authorize the purchase of a policy greater in amount. The premium on said insurance policy shall be paid by the board of county commissioners from the county general fund.