[Emphasis added for clarity.] Here's a chart of the results.
But we are decidedly NOT special when it comes to what they call "system support" -- we have only middling amounts of confidence that our government embodies the rule of law and is doing its job for all citizens. It is a little amazing to see that citizens of El Salvador, Honduras and Mexico -- all of which look from afar like unstable, lawless kleptocracies -- think their governments are more legitimate than we think ours is.
In this research, younger people in the United States generally expressed less "system support" than older people. I can only assume that they simply don't think government is working for them.
The U.S. is a big country with a lot of different people. It would be interesting to see results from within the country broken out by racial, income, and religious groups. Is lack of "system support" -- of government legitimacy -- more pronounced among some groups than others? Which groups?
Governments that survive work to reduce whatever social shortcomings reduce system support. Even capitalists should understand this. The customers can get antsy.