If you live in Europe or North America and have enabled SpotPass on New Super Mario Bros. 2 you should have recently received your first update to let you know how many coins have been collected by Mario fans globally.
A few days ago Japanese players got their first update, at that time the global total was a mere 36.5 billion. It has now increased to a whopping 50,610,416,353 coins which will no doubt be turning Wario green with envy.