Note that Shodan doesn't try to login using default credentials. If you see banners advertising their defaults it just means that the device is telling you what its defaults are - it doesn't mean that the device is still using them.

That being said, a ton of devices still use default credentials but we don't have any numbers on how many exactly.

I wasn't implying Shodan did this. Shodan just lets you find things. Google reveals default passwords quite readily though. It's alarming how often they work to login.

Ah yeah, I didn't think you were :) It's just a common misconception so I wanted to let readers here know.

Or there is no password at all, like say a lot of HP printers.

On Konica-Minolta printers the password is almost always the same. My school IT admin explained that they're pretty much always rented or "bought" with a mandatory support contract and the contractors get really annoyed when the admin password isn't the default one, since it's supposed to be "their" password.