I wouldn't go as high as 99% anymore.
Legacy channel numbers seem to matter these days to maybe 75% of markets. There are a growing number where stations have figured out that viewers see them at different spots all over the dial (cable and satellite positioning, for instance, in areas with high penetration), and we're seeing those stations go to different forms of branding, whether it's just calls or network/city.
This is especially true for stations that may not even have existed in the analog era. If you're NBC Fort Wayne (WPTA 21.2) and you're on five different channel numbers depending on the system, you just want to be "NBC Fort Wayne" and leave it there.
For legacy stations that have spent 60 or 75 years building an identity around their channel number? That's a different story. Ask 100 people in Denver where they go for 60 Minutes and 98 of them will say "channel 4."
You don't throw away that kind of consumer recognition just for the hell of it. (Which makes it odd that CBS has chosen to do just that for what's now branded as "CBS Colorado.")