We are the largest managed care company in Puerto Rico in terms of membership, with over 45 years of experience in the managed care industry. We offer a broad portfolio of managed care and related products in the Commercial, Commonwealth of Puerto Rico Health Reform (the Reform) and Medicare (including Medicare Advantage and the Part D stand-alone prescription drug plans (PDP)) markets. The Reform is a government of Puerto Rico-funded managed care program for the medically indigent, similar to the Medicaid program in the U.S. We have the exclusive right to use the Blue Shield name and mark throughout Puerto Rico, serve approximately one million members across all regions of Puerto Rico and hold a leading market position covering approximately 25% of the population. For the years ended December 31, 2007 and 2006 respectively, our managed care segment represented approximately 86.1% and 88.6% of our total consolidated premiums earned, net, and approximately 78.3% and 62.2% of our operating income. We also have significant positions in the life insurance and property and casualty insurance markets. Our life insurance segment had a market share of approximately 15% (in terms of premiums written) as of December 31, 2006. Our property and casualty segment had a market share of approximately 9% (in terms of direct premiums) as of December 31, 2006.
Medical premiums generated by the Commercial sector decreased by $21.3 million, or 2.9%. This decrease was due to a decrease in member months of 359,262, or 6.4%, primarily as a result of the loss of several fully-insured accounts due to aggressive pricing by our competitors as well as qualified enrollees transferring to our or our competitors’ Medicare Advantage policies and fully-insured groups changing to self-funded arrangements, offset in part by an average increase in premium rates of approximately 3.7%.
Administrative service fees increased by $1.4 million, or 9.0%, to $16.9 million during the 2006 period due to an increase in member months enrollment of self-funded arrangements of 21,117, or 1.1%, and increases in fee rates.
Underwriting and other expenses for the segment increased by $1.7 or 3.7%, during the year ended December 31, 2007. Considering the effect of underwriting and other expenses of $1.7 million incurred by GA Life during the month of January 2006, net of the effect of the coinsurance agreement, the underwriting and other expenses of the segment remained flat during the 2007 period. The segment’s operating expense ratio increased by 0.7 percentage points during the year 2007, from 52.7% in 2006 to 53.4% in 2007.
Purchase obligations represent payments required by us under material agreements to purchase goods or services that are enforceable and legally binding and where all significant terms are specified, including: quantities to be purchased, price provisions and the timing of the transaction. Other purchase orders made in the ordinary course of business for which we are not liable are excluded from the table above. Estimated pension plan contributions amounting to $5.0 million were included within the total purchase obligations. However, this amount is an estimate which may be subject to change in view of the fact that contribution decisions are affected by various factors such as market performance, regulatory and legal requirements and plan funding policy.
To monitor the solvency of the operations, the BCBSA requires us and our managed care subsidiary to comply with certain specified levels of risk-based capital (RBC). RBC is designed to identify weakly capitalized companies by comparing each company’s adjusted surplus to its required surplus (RBC ratio). The RBC ratio reflects the risk profile of insurance companies. At December 31, 2007, both we and our managed care subsidiary’s estimated RBC ratio were above the 200% of our RBC required by the BCBSA and the 375% of our RBC level required by the BCBSA to avoid monitoring.
Médicos. Both syndicates were organized for the purpose of underwriting medical-hospital professional liability insurance. As a member, the property and casualty insurance segment shares risks with other member companies and, accordingly, is contingently liable in the event the previously mentioned syndicates cannot meet their obligations. During 2007, 2006 and 2005, no assessment or payment was made for this contingency. It is the opinion of management that any possible future syndicate assessments will not have a material effect on our operating results and/or cash flows, although there is no ceiling on these payment obligations.