Our results are impacted by many factors, but most notably are influenced by our ability to establish and maintain a competitive and efficient cost structure and to accurately and consistently establish competitive premium, ASO fee, and plan benefit levels that are commensurate with our medical and administrative costs. Medical costs are subject to a high rate of inflation due to many forces, including new higher priced technologies
Membership in Medicare Advantage products grew by 180,600 members, or 47.9%, from December 31, 2004, including 130,200 members from sales primarily related to our new PFFS offering, and 50,400 members from the acquisition of CarePlus Health Plans of Florida.
In December 2004, the Financial Accounting Standards Board issued SFAS No. 123R, Share-Based Payment, or SFAS 123R, which requires companies to expense the fair value of employee stock options and other forms of stock-based compensation. This requirement represents a significant change because fixed-based stock option awards, a predominate form of stock compensation for us, were not recognized as compensation expense under Accounting Principles Board Opinion No. 25, Accounting for Stock Issued to Employees. SFAS 123R requires that the cost of the award, as determined on the date of grant at fair value, be recognized over the period during which an employee is required to provide service in exchange for the award (usually the vesting period). The grant-date fair value of the award will be estimated using option-pricing models. In addition, certain tax effects of stock option exercises will be reported as a financing activity rather than an operating activity in the statements of cash flows. We adopted SFAS 123R on January 1, 2006 under the retrospective transition method using the Black-Scholes pricing model. The effect of expensing stock options under a fair value approach using the Black-Scholes pricing model reduced diluted earnings per common share, as retroactively restated for the adoption of SFAS 123R, by $0.08 in 2005, $0.06 in 2004, and $0.03 in 2003 as more fully disclosed in Note 2 of the consolidated financial statements included in Item 8.-Financial Statements and Supplementary Data. In addition, the classification of cash inflows from any excess tax benefit associated with exercising stock options will change from an operating activity to a financing activity in the consolidated statements of cash flows with no impact on total cash flows. We estimate the impact of this change in classification will decrease operating cash flows (and increase financing cash flows) by approximately $15.5 million in 2005, $3.7 million in 2004, and $15.2 million in 2003.
Our effective tax rate in 2005 of 26.9% decreased 5.8% compared to the 32.7% effective tax rate in 2004. The effective tax rate for 2005 reflects the favorable impact from the resolution of a contingent tax gain of $22.8 million during the first quarter of 2005 in connection with the expiration of the statute of limitations on an uncertain tax position related to the 2000 tax year. See Note 8 to the consolidated financial statements included in Item 8.-Financial Statements and Supplementary Data for a complete reconciliation of the federal statutory rate to the effective tax rate. We expect the 2006 effective tax rate to be in the range of 35% to 37%.
Premium revenues increased 7.3% to $12.7 billion for 2004, compared to $11.8 billion for 2003. Higher premium revenues resulted primarily from the Ochsner acquisition, as more fully described in Note 3 to the consolidated financial statements included in Item 8.-Financial Statements and Supplementary Data, and an increase in Medicare Advantage and fully insured commercial average per member premiums. Items impacting average per member premiums include changes in premium rates as well as changes in the geographic mix of membership, the mix of product offerings, and the mix of benefit plans selected by our membership.
(3) Purchase and other obligations include agreements to purchase services, primarily information technology related services, or to make improvements to real estate, in each case that are enforceable and legally binding on us and that specify all significant terms, including: fixed or minimum levels of service to be purchased; fixed, minimum or variable price provisions; and the appropriate timing of the transaction. Purchase obligations exclude agreements that are cancelable without penalty.
(a) Reflects estimated potential changes in medical and other expenses payable caused by changes in completion factors for incurred months prior to the most recent three months.
SFAS 142 requires a two-step process to review goodwill for impairment. The first step is a screen for potential impairment, and the second step measures the amount of impairment, if any. Impairment tests are performed, at a minimum, in the fourth quarter of each year supported by our long-range business plan and annual planning process. Impairment tests completed for 2005, 2004 and 2003 did not result in an impairment loss.
We estimate the costs of our medical claims and other medical expense payments using actuarial methods and assumptions based upon claim payment patterns, medical cost inflation, historical developments such as claim inventory levels and claim receipt patterns, and other relevant factors, and record medical claims reserves for future payments. We continually review estimates of future payments relating to medical claims costs for services incurred in the current and prior periods and make necessary adjustments to our reserves.
The results of operations and financial condition of Corphealth, CarePlus and Ochsner have been included in our consolidated statements of income and consolidated balance sheets from the respective acquisition dates. The pro forma financial information presented below assumes that the acquisitions of Corphealth, CarePlus and Ochsner had occurred as of the beginning of each respective period. The pro forma adjustments include the pro forma effect of amortization of other intangible assets arising from the purchase price allocation and interest expense related to the assumed financing of the cash purchase price and the associated income tax effects of the pro forma adjustments. The pro forma results have been prepared for comparative purposes only and do not purport to be indicative of the results of operations that would have occurred had the Corphealth, CarePlus and Ochsner acquisitions been consummated at the beginning of the respective periods.
At December 31, 2005, the fair value of our swap agreements related to the 6.30% senior notes was in our favor by $10.9 million and is included in other long-term assets and the fair value of our swap agreements related to the 7.25% senior notes was out of our favor by $4.8 million and is included in trade accounts payable and accrued expenses. Likewise, the carrying value of our senior notes has been increased $6.1 million to reflect their fair value. The counterparties to our swap agreements are major financial institutions with which we also have other financial relationships.
In our opinion, the accompanying consolidated balance sheets and the related consolidated statements of income, of stockholders’ equity and of cash flows present fairly, in all material respects, the financial position of Humana Inc. and its subsidiaries at December 31, 2005 and 2004, and the results of their operations and their cash flows for each of the three years in the period ended December 31, 2005 in conformity with accounting principles generally accepted in the United States of America. In addition, in our opinion, the financial statement schedules listed in the index appearing under Item 15 (2) present fairly, in all material respects, the information set forth therein when read in conjunction with the related consolidated financial statements. These financial statements and financial statement schedules are the responsibility of the Company’s management. Our responsibility is to express an opinion on these financial statements and financial statement schedules based on our audits. We conducted our audits of these statements in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit of financial statements includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.