If it was an official report by PayPal, we could believe that, but a third-party survey is bound to have some huge methodological errors, like it often happens in crypto.
That’s really an overly exaggerated statement echoed on the media: The survey is not a global survey on Paypal users (even if it is delimited to the USA), but rather subject to Mizuho Securities USA customers, as is inferred by the references left below, and carried out on 380 "users" (stated on Coindesk’s link).
So, 17% of people with strong investment background used PayPal's Bitcoin trading - that's what this survey means. Pretty useless fact, as it tells us nothing about the global picture.
Twenty per cent of ALL Paypal users in the US? I find that totally impossible to believe. I doubt 20% of them even know it's there, let alone have had a dabble. Paypal is something you mindlessly log into to buy something. Not many go much further or explore whatever else it offers.
If some millions of people suddenly got into Bitcoin, it would have been noticeable on things like Google trends or twitter activity, but we've seen no such things lately.