2005 by $869 million, or 1.8%, compared to 2004. The foreign exchange impact on 2006 revenue growth was due to the strengthening of the U.S. dollar relative to many foreign currencies, especially the Japanese yen and the euro, partially offset by the weakening of the U.S. dollar relative to the Canadian dollar, the total of which accounted for about 96% of the impact in 2006. The favorable impact of foreign exchange on 2005 revenue growth was due to the weakening of the U.S. dollar relative to many foreign currencies, especially the euro which accounted for about 36% of the impact in 2005. The revenues of legacy Pharmacia products, recorded from the acquisition date of April 16, 2003, until the anniversary date of the transaction in 2004, were treated as incremental volume and did not have a significant foreign exchange impact.

Revenues exceeded $500 million in each of 10 countries outside the U.S. in 2006 and in 2005. The U.S. was the only country to contribute more than 10% of total revenues in each year.

Our policy relating to the supply of pharmaceutical inventory at domestic wholesalers, and in major international markets, is to maintain stocking levels under one month on average and to keep monthly levels consistent from year to year based on patterns of utilization. We have historically been able to closely monitor these customer stocking levels by purchasing information from our customers directly or by obtaining other third-party information. We believe our data sources to be directionally reliable, but cannot verify their accuracy. Further, as we do not control this third-party data, we cannot be assured of continuing access. Unusual buying patterns and utilization are promptly investigated.

Revenues

Total revenues increased 2% to $48.4 billion in 2006, primarily due to the solid aggregate performance in our broad portfolio of patent-protected medicines and the revenues from new products launched over the past three years. These increases were mostly offset by the loss of U.S. exclusivity on Zithromax in November 2005 and Zoloft in June 2006, which resulted in a collective decline in revenues of about $2.5 billion for these two products. In 2006, Lipitor, Norvasc, Zoloft and Celebrex each delivered at least $2 billion in revenues, while Lyrica, Viagra, Detrol/Detrol LA, Xalatan/Xalacom and Zyrtec each surpassed $1 billion.

The decline in total rebates for 2006 reflects:

• The implementation of the Medicare Act, effective January 1, 2006, which caused a shift from Medicaid rebates to Medicare rebates. The shift is a result of patients who are eligible for Medicare and Medicaid and who now receive their prescription drug benefits through Medicare instead of Medicaid, as well as shifts to managed care.

• Lower rebates for Medicaid, Medicare and performance- based contracts due to lower sales of Zithromax, which lost exclusivity in the U.S. in November 2005, and Zoloft, which lost exclusivity in the U.S. in June 2006.

• Lower performance-based contract rebates due to the expiration of our contract with Express Scripts Inc. in December 2005.

Performance-based contracts are with managed care customers, including health