It's actually not
that far of the mark. There's a LOT more cash out there than you probably think, and no one really know where is it and what's it being used for.
As an example, 80% of the bills in circulation in the US are 100$ bills. It's so much cash that "The average person would be having to carry around 35 or 36 of them in their house or in their wallet. This is for every man, woman, and child."
And according to the federal reserve, the demand for large bills comes mostly from border states - Florida, California and Texas.
Source: https://freakonomics.com/podcast/still-using-cash/
