Villain is running 56/31/14 over 50 hands and folding to cbets 0%. How often are they on a complete bluff on the river?

$0.25/$0.5 No Limit Holdem
6 players
Converted at weaktight.com

Stacks:
UTG ($38.10)
UTG+1 ($38.45)
CO ($77.90)
Hero ($59.05)
SB ($49.50)
BB ($46.85)

Pre-flop: ($0.75, 6 players) Hero is BTN
UTG raises to $1.5, 2 folds, Hero calls $1.5, 1 fold, BB calls $1

Flop: ($4.75, 3 players)
BB checks, UTG bets $3, Hero raises to $9, BB folds, UTG calls $6

Turn: ($22.75, 2 players)
UTG checks, Hero checks

River: ($22.75, 2 players)
UTG goes all-in $27.6, Hero calls $27.6

[Results Hidden]