Who is holding all those U.S. dollars?

Snipet from article...http://www.econbrowser.com/archives/2013/04/who_is_holding.html

If recent trends continue, in a few months there will be $1.2 trillion in Federal Reserve notes (otherwise known as dollar bills) in circulation. Who is holding all these?
One clue comes from looking at the denominations: 3/4 of the currency held by the public is in the form of hundred-dollar bills.

 So...this article is basically about where the majority of U.S. currency is concentrated and how this affects our economy. The author argues that U.S. benefits from the majority of our large bills being held by investors in other countries. Despite our economic instabilities the U.S. dollar is still considered as a safe place to store wealth.

Is the fact that foreign holders have a large portion of U.S. currency a good thing? What role does public opinion about the banking system play in the results of this article? What might this article suggest about economic growth in the U.S.?

HINT: look at graphs and read comments they're actually pretty thought provoking =)