I think you can get almost any figure, depending on where you place the goalposts in the definition of technical debt.

Two programmers who hate each other's code can call each other's code "technical debt" while extolling the virtues of their own.

Operating systems, languages, run-times, editors, browsers, websites, social networks, .... that I don't use are all technical debt that should die. Don't you lay your deleting paws on what I do use, though!

The term "technical debt" has about as much content as "suckage", "bloat" or "cruft". It sounds more intellectual though.

It's a technical term: I mean, for Pete's sake, just look at it: it has "technical" right in it, so how can it not be! "Debt" is from finance, which gives it an air of credibility with anyone in your organization who approves expenses.