According to a recent survey,

77% of employers spent 16% or more of their total health care budgets on pharmacy benefits in 2014, up from 71% in 2013.

Source: "Majority of Employers Spend 16 Percent or More of Health Care Budget on Pharmacy Benefits: Buck Consultants Survey," Buck Consultants at Xerox Press Release, February 25, 2015, http://news.xerox.com/news/5th-Annual-Buck-Consultants-at-Xerox-Prescription-Drug-Benefit-Survey