USD ?? To PHP

[Dave Hounddriver]

Quote

 The Federal Reserve estimates that the majority of the cash in circulation today is outside the United States.

https://www.newyorkfed.org/aboutthefed/fedpoint/fed01.html

Since the majority of US dollars are outside the country then the currency value will fluctuate depending on how much of that cash is getting exchanged for other currencies.  Supply and demand.  If and when another currency supersedes the dollar as the safest currency to keep your money then the value of the US dollar will fall . .  perhaps quickly.  Fortunately for the US, that does not seem likely in the immediate future.