More like 3% on the desktop. Mobile is not really relevant here. The URL bar on those devices is obviously shorter to begin with because of less display width. So just showing the hostname is not much different than showing the hostname + 5 characters.

Reminds me of a great phishing attack I saw the other year:

"https://support.google.com.verify.x82loo2a.com"

Of course, in a tiny url bar, you'd just see "https://support.google.com.veri".