We began operating under new contracts with the State of Ohio to manage care for 37,200 Medicaid members by entering seven new counties in the East Central market on July 1, 2006, and 17 new counties in the Northwest market on October 1, 2006.
Effective October 1, 2006, we began performing under our contract with the Arizona Health Care Cost Containment System to provide long-term care services in the Maricopa, Yuma and LaPaz counties in Arizona.
Effective July 1, 2005, we began performing under our contract with the State of Arizona to facilitate the delivery of mental health and substance abuse services to behavioral health recipients in Arizona.
Our Medicaid Managed Care segment generates revenues primarily from premiums we receive from the states in which we operate health plans. We receive a fixed premium per member per month pursuant to our state contracts. We generally receive premium payments during the month we provide services and recognize premium revenue during the period in which we are obligated to provide services to our members. Some states enact premium taxes or similar assessments, collectively, premium taxes, and these taxes are recorded as G&A expenses. Some contracts allow for additional premium related to certain supplemental services provided such as maternity deliveries. Revenues are recorded based on membership and eligibility data provided by the states, which may be adjusted by the states for updates to this data. These adjustments have been immaterial in relation to total revenue recorded and are reflected in the period known.
In 2005, we increased our membership in Ohio through our acquisition of the Medicaid-related assets of SummaCare, Inc. Our membership increased in Indiana, New Jersey and Wisconsin from additions to our provider networks, expansion into SSI in Wisconsin, increases in counties served and growth in the overall number of Medicaid beneficiaries. In Kansas, we increased our membership by eliminating a ceiling on our membership total with the State. Our membership decreased in Missouri and Texas because of more stringent eligibility requirements for the Medicaid and SCHIP programs.
Our medical costs include payments to physicians, hospitals, and other providers for healthcare and specialty services claims. Medical costs also include estimates of medical expenses incurred but not yet reported, or IBNR, and estimates of the cost to process unpaid claims. Monthly, we estimate our IBNR based on a number of factors, including inpatient hospital utilization data and prior claims experience. As part of this review, we also consider the costs to process medical claims and estimates of amounts to cover uncertainties related to fluctuations in physician billing patterns, membership, products and inpatient hospital trends. These estimates are adjusted as more information becomes available. We employ actuarial professionals and use the services of independent actuaries who are contracted to review our estimates quarterly. While we believe that our process for estimating IBNR is actuarially sound, we cannot assure you that healthcare claim costs will not materially differ from our estimates.
Actuarial Standards of Practice generally require that medical claims liabilities estimates be adequate to cover obligations under moderately adverse conditions. Moderately adverse conditions are situations in which the actual claims are expected to be higher than the otherwise estimated value of such claims at the time of estimate. In many situations, the claims amounts ultimately settled will be different than the estimate that satisfies the Actuarial Standards of Practice.