Viagra, Norvasc, Zyvox, Xalatan/Xalacom (Xalatan lost exclusivity in the U.S. in March 2011), Sutent, Geodon/Zeldox, and the Premarin family each surpassed $1 billion in revenues.

In 2010, Lipitor, Enbrel, Lyrica, Prevnar 13/Prevenar 13 and Celebrex each delivered at least $2 billion in revenues, while Viagra, Xalatan/ Xalacom, Effexor (Effexor XR lost exclusivity in the U.S. in July 2010), Norvasc, Prevnar/Prevenar (7-valent), Zyvox, Sutent, the Premarin family, Geodon/Zeldox and Detrol/Detrol LA each surpassed $1 billion in revenues.

Revenues exceeded $500 million in each of 16 countries outside the U.S. in 2012 and 2011, and in each of 17 countries outside the U.S. in 2010. The U.S. and Japan were the only countries to contribute more than 10% of total revenue in 2012. The U.S. was the only country to contribute more than 10% of total revenues in 2011 and 2010.

Our policy relating to the supply of pharmaceutical inventory at domestic wholesalers, and in major international markets, is to generally maintain stocking levels under one month on average and to keep monthly levels consistent from year to year based on patterns of utilization. We historically have 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.

As is typical in the biopharmaceutical industry, our gross product sales are subject to a variety of deductions, that generally are estimated and recorded in the same period that the revenues are recognized and primarily represent rebates and discounts to government agencies, wholesalers, distributors and managed care organizations with respect to our pharmaceutical products. These deductions represent estimates of the related obligations and, as such, judgment and knowledge of market conditions and practice are required when estimating the impact of these sales deductions on gross sales for a reporting period. Historically, our adjustments to actual results have not been material to our overall business. On a quarterly basis, our adjustments to actual results generally have been less than 1% of biopharmaceutical net sales and can result in either a net increase or a net decrease in income. Product-specific rebate charges, however, can have a significant impact on year-over-year individual product growth trends.

 The following table provides information about certain deductions from revenues:

The total rebates, chargebacks and sales allowances for 2012 were lower than 2011, primarily as a result of:

• the impact of decreased Medicaid, Medicare and performance-based contract rebates contracted for Lipitor and certain other products that have lost exclusivity;

• changes in product mix; and

• the impact on chargebacks of decreased sales for certain products that have lost exclusivity, partially offset by, among other factors:

• an increase in chargebacks for our branded