The United States represents about 40 percent of global pharmaceutical sales, but last year it accounted for only a quarter of the growth, according to IMS Health. The Norwalk, Connecticut-based market research firm reported that global pharmaceutical sales grew to $712 billion in 2007, a 6.4 percent increase. IMS said Asian markets outside of Japan saw the most robust growth with more than a 13 percent increase. That was fueled by increased access to healthcare, the firm said.  Sales in China grew 25.7 percent, while sales in India rose 13 percent and sales in Korea increased 10.7 percent. Lipitor was the top selling drug worldwide with sales of $1.5 billion, but it represented a 2.8 percent drop from 2006.