Health insurance premiums typically increase on an annual basis. The percentage increase varies greatly but tends to be between 3% and 10%. On average, the annual increase is about 7%. It is impossible to predict future health insurance premiums so you should enter the percentage increase that you feel is most reasonable. The percentage you enter has no effect on the estimated value of your sick leave credits at termination. The estimated future cost of health insurance premiums will only affect the estimate of how long your sick leave credits may last in retirement.