The two drugs together accounted for about 30 percent of Pfizer's sales, and an even higher share of its profit.

The new drugs account for $10 billion in annual sales and 90 percent of the national market for antipsychotics.

The drug accounted for 79 percent of MedImmune's sales in 2000.

By 1988, illicit drugs accounted for $4 billion annually in earnings-more foreign exchange than all of Pakistan's legal exports combined.

The two drugs accounted for $6.6 billion, or 46 percent, of Amgen's $14.3 billion in 2006 revenue.

But in 2005, drug using patients accounted for more than 50%.

Those drugs account for about 80 percent of the $25 billion in annual prescription-drug sales of pharmaceutical manufacturers.

Meanwhile, the organization says that generic drugs are accounting for an increasing percentage of prescriptions, taking business away from brand-name pharmaceutical companies.

But, Ms. Hofelich said, the costs were so much lower that those drugs accounted for only 12 percent of drug spending.

Costly new drugs and rising prescription volumes account for much of the premium increases.