It's hard to even estimate. I'd imagine maybe 10% of all kmongers ever wrote a single review online, and that number is literally me completely guessing.

 
Then the segmented sites. For bay area, it appears that ter was never the primary spot to write reviews until it came back this year, which coincided with the other site kicking the kprofiles out.

 
If we're talking reviews in plural, we're talking about a fraction of a percent, and single digit percent in absolute best case, imo.

For many popular girls, it can be between 1 and 5 percent, I think. You have to allow for many repeats with popular girls. The first session/monger pairing gets a review. You can sort of guesstimate how many are writing reviews if you know about how busy she is. But the same monger sees her some n number of times with usually no additional reviews. But some popular girls are kept quiet because mongers want to keep the secret to themselves. So for them the percentage is vanishingly small.  

 
For less popular girls, it’s less than that. But very hard to pin down a number.  

 
Frankly, I wouldn’t even try to assign a hard number here as the data is just too soft. The 1 and 5 percent is a total swag. But this question has come up before. And some people thought those numbers made sense. Up to you what you want to believe, though.

TER has NEVER been very popular in the Mid-Continent area and even less so in the post FOSTA/SESTA era. There are dozens of K-AMPs in Dallas, along with a handful of K AAMPs. The K-AAMPs have maybe a dozen girls working on any given day combined which translates to somewhere just under a 100 K-Girl sessions each day, or lets cut in in half and say  that on an average day there are 50 different guys seeing a K-Girl at an AAMP in Dallas. It's rare to see more than a single review each week for a K-Girl in Dallas so you do the math, it's a very tiny percentage of K-Girl sessions that are reviewed on TER from Dallas, way less than even 1%.