For example, let's assume that a service member has served in the military for 4 years before marrying their spouse. Let's also assume that he/she then served another 16 years before retiring, while still married. After retirement, the couple separates and divorces. In this case, 16 of the service member’s 20 years on active duty occurred during the marriage and before separation and divorce. That means the numerator of the marital share fraction would be 16 and the denominator would be 20.
16 divided by 20 = 80%