Perhaps I already have--just not on purpose.
I found an interesting set of statistics in the book Non-Profit Organizations: Cases and Materials (3d ed. 2006) by James J. Fishman and Stephen Schwartz (I'm using this book for a school project; an online version doesn't seem to be available, sorry). Health care is the single largest sub-sector in the service providing non-profit sector (service providing excludes religious organizations), absorbing 60 percent of non-profit revenues and 25 percent of charitable contributions. Fishman & Schwartz at 22. Further, hospital care represents the single largest component of health care in the United States. Id. at 24.
Now here comes the interesting part: the break down of Hospital Care. Non-profit hospitals comprise about half of all hospitals. Id. Non-profit does not mean not profitable, but rather tax exempt and prohibited from distributing profits. Id. at 3. So for those non-profit hospitals that do earn a profit (not all do!) those revenues must be reinvested into the provision of services rather than distributed to owners. There is no investment incentive in a non-profit; revenues must come from fees for services, government grants or charitable contributions. Id. at 18.
The second largest group of Hospitals in the U.S. are government hospitals at 31 percent. Id. at 25. Government hospitals mean run by a governmental authority, mostly at the state and local level. Id.
Then for-profit hospitals are only 19 percent of all hospitals. Id. And they seem to be smaller as the account for only 14 percent of hospital beds. Id.
What does this all mean for this debate? On the one hand you might look at the numbers and say, "See, Pink, the market doesn't need to regulate health care; as you said quality is great. Such great quality is delivered without a significant market incentive for investment! Let's socialize that pesky 19 percent!"
On the other hand, you can just as easily say (as I will, predictably), "Perhaps many of the ills in our health care system, such as lack of access, are created by the lack of market incentives for the majority of hospitals."