Depending on what stats you use...
That about 18% of the world value...
The stats I used:
As for money owed by every single person and country in the world, the grand total is $215 trillion, with some 33% of it borrowed in the last decade.

Using the high end estimate that 4% of the world money supply(including debts/derivatives ...
Source: https://www.marketwatch.com/story/this-is-how-much-money-exists-in-the-entire-world-in-one-chart-2015-12-18

There comes a time-How much of XRP value is based on the idea of "cheap"?