Medical devices encompass an extremely wide range of products, such as surgical gloves, dental instruments, wheelchairs, coronary stents, artificial knees and hips, defibrillators, cardiac pacemakers, irradiation equipment, and advanced imaging technology. The U.S. medical device industry has estimated total sales of $106 billion to $116 billion a year. A few large firms account for the lion's share of this revenue. For example, Johnson and Johnson's worldwide sales of medical devices and diagnostics totaled $26 billion in 2011; the firm had total sales (on both medical devices and other products) of $65 billion, on which it earned profits of nearly $10 billion. Medtronic had $16 billion in sales and profits of $3 billion in its 2011 fiscal year. One trade group has estimated that the ten largest medical device makers will account for 86 percent of the sales of covered medical devices and hence pay 86 percent of the receipts from the excise tax.