We operate in one segment-BioPharmaceuticals. For additional information about business segments, refer to "Item 8. Financial Statements and Supplementary Data-Note 1. Accounting Policies and Recently Issued Accounting Standards." Our principal strategy is to combine the resources, scale and capability of a pharmaceutical company with the speed and focus on innovation of the biotech industry. Our focus as a specialty biopharmaceutical company is on discovering, developing and delivering transformational medicines for patients facing serious diseases. Our four strategic priorities are to drive business performance, continue to further build a leading franchise in IO, maintain a diversified portfolio both within and outside of IO, and continue our disciplined approach to capital allocation, including establishing partnerships, collaborations and in-licensing or acquiring investigational compounds as an essential component of successfully delivering transformational medicines to patients. We expect that our planned acquisition of Celgene that we announced in January 2019 will enable us to create a leading focused specialty biopharmaceutical company that is well positioned to address the needs of patients with cancer, inflammatory, immunologic or cardiovascular diseases through high-value innovative medicines and leading scientific capabilities. We plan to remain focused while broadening our portfolio of marketed medicines and pipeline assets. With complementary disease areas, the combined company will operate with global reach and scale, the speed and agility that is core to each company's strategic approach. For a further discussion of our strategy initiatives, see "Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations-Strategy."
We compete with other worldwide research-based drug companies, smaller research companies and generic drug manufacturers. Our products are sold worldwide, primarily to wholesalers, retail pharmacies, hospitals, government entities and the medical profession. We manufacture products in the U.S., Puerto Rico and in four foreign countries. Most of our revenues come from products in the following therapeutic classes: oncology; cardiovascular and immunoscience.
The percentage of revenues by significant region/country were as follows: