How profitable are health insurance companies?

Here is one report:

Health insurers, in fact, ranked below many other industries in
profitability, including other health sectors, according to the latest
Fortune magazine rankings. While pharmaceutical companies were the
third-most profitable industry last year, with a 19.3 percent profit
margin, health insurers ranked 35th, with a 2.2 percent profit margin.
Health insurers also ranked lower in profitability than medical
products and equipment makers, pharmacies and medical facilities.

Here is a related list on relative profitability.  It's true that profits are up a lot in percentage terms since 2000 but that doesn't mean profits are high.  Of course it is possible these accounting measures of profit are lies or misleading.

Here are the share prices of Aetna over time and make sure you notice the splits.  It's not clear we can infer anything from this data (for instance if the monopoly position were evident from the beginning, equity returns would be quite modest), but if you wish you can peruse Yahoo Finance for evidence.  I don't find it.  Recent low equity returns may be the downturn at work but the original question is how profitable these companies are in absolute terms.

I'm very willing to "Cry Uncle" on this one because all I've done is some blogger research using Google.  But I would genuinely like to know: if you favor a public plan, or if you think insurance companies are holding strong monopoly positions, what is your evidence for their extreme profitability?  If you go to the second link you'll see lots of people claiming the companies are very profitable and should be squeezed in some manner.  Or do you simply think the companies are not very profitable?

I thank Robert Olson and several other MR readers for related queries.