Pfizer is one of the world's largest pharmaceutical firms, with annual sales over $50 billion. Pfizer also spends a leading amount on research and development, close to $8 billion annually. While Pfizer historically sold many types of healthcare products and chemicals, now, prescription drugs and vaccines account for the majority of sales. Top sellers include pneumococcal vaccine Prevnar 13, neuroscience drug Lyrica, cancer drug Ibrance, cardiovascular treatment Eliquis, and immunology drug Xeljanz. Pfizer sells these products globally, with international sales representing close to 50% of its total sales. Within international sales, emerging markets are a major contributor, representing over a fifth of total company sales.