The following table sets forth our summary financial data. This information should be read in conjunction with our consolidated financial statements and the related notes and "Management's Discussion and Analysis of Financial Condition and Results of Operations" included in this 2015 Form 10-K.
Medical benefits ratio ("MBR") measures the ratio of our medical benefits expense to premium revenue excluding reimbursement for Medicaid premium taxes and Medicaid ACA industry fee reimbursement revenue. Because the effect of reimbursements for Medicaid premium tax and ACA industry fee are included in the premium rates or reimbursement established in certain of our Medicaid contracts and also recognized separately as a component of expense, we exclude these reimbursements from premium revenue when calculating key ratios as we believe that their effect is not indicative of operating performance. For GAAP reporting purposes, Medicaid premium taxes and Medicaid ACA industry fee reimbursements are included in premium revenue.
In May 2015, our Staywell Health Plan was selected by the Florida Healthy Kids Corporation ("FHKC") to continue providing managed care services for children as part of the Florida Healthy Kids program in nine regions. These regions include the Pensacola, Tallahassee, Gainesville, Jacksonville, Fort Lauderdale, Fort Myers and Miami metropolitan areas. As of December 31, 2015, we served approximately 55,000 Florida Healthy Kids members. The contract commenced on October 1, 2015 and is for a term of two years, which may be extended for two additional one-year terms at FHKC’s discretion.
For the year ended December 31, 2015, our net income increased by $54.9 million, or 86.2%, compared to the same period of 2014, primarily attributable to improved performance in all segments, due to our Medicare bid positioning for the 2015 plan year, organic growth in our Medicaid membership and improved pharmacy rebates management, partially offset by the increase in unreimbursed ACA industry fee expense for 2015. Refer to Segment Reporting below for a discussion of current developments, operating results and other key performance measures by reportable segment.
Premium revenue for the year ended December 31, 2014 increased approximately $3.4 billion, or 35.8%, compared to the same period in 2013, due mainly to the effect of organic membership growth across all of our segments and the Windsor acquisition, which accounted for a combined increase in Medicare Health Plans and Medicaid PDPs segment revenue of $620.5 million for the year ended December 31, 2014. Additionally, the increase was due to the effect of the ACA fee reimbursement from our Medicaid state customers, the favorable effect of Medicaid membership mix changes and the benefit of a full year of premiums for our South Carolina and Missouri Medicaid plans that were acquired in the first quarter of 2013. These increases were partially offset by rate decreases in our Medicare Health Plans segment and a lower rate in our Medicare PDPs segment, consistent with our 2014 bids.
Medicare Health Plans premium revenue in 2015 decreased $64.4 million, or 1.6%, compared to the same period in 2014, primarily resulting from the decline in membership as a result of our 2015 bid actions, which included exiting two counties in California, as well as exiting from MA in Arizona, Missouri and Ohio. The decline also reflects the divestiture of our Medicare Supplement business effective July 1, 2015, partially offset by organic membership growth in Florida and Texas.
incur restrictions on the ability of our subsidiaries to pay dividends, make other payments and guarantee indebtedness;
Represents the principal amount of our outstanding Senior Notes and Term Loan as of December 31, 2015. These amounts exclude the remaining $12.1 million debt premium on the Senior Notes, which is being amortized over the remaining term of the Senior Notes.