NL100: K5o flops TPLK, turn checks, villain makes a big bet at river

[Aquadougs]

Villain just entered the table

Party Poker, $0.50/$1 NL Hold'em Cash Game, 5 Players
LeggoPoker.com - Hand History Converter

CO: $98.50
Hero (BTN): $103.63
SB: $240.30
BB: $160.54
UTG: $98.55

Pre-Flop: 5[img]/images/graemlins/diamond.gif[/img] K[img]/images/graemlins/heart.gif[/img] dealt to Hero (BTN)
2 folds, <font color="red">Hero raises to $4</font>, SB folds, BB calls $3

Flop: ($8.50) K[img]/images/graemlins/diamond.gif[/img] 2[img]/images/graemlins/spade.gif[/img] 3[img]/images/graemlins/spade.gif[/img] (2 Players)
BB checks, <font color="red">Hero bets $6</font>, BB calls $6

Turn: ($20.50) 9[img]/images/graemlins/spade.gif[/img] (2 Players)
BB checks, Hero checks

River: ($20.50) J[img]/images/graemlins/diamond.gif[/img] (2 Players)
<font color="red">BB bets $20.29</font>, Hero calls $20.29


What do you think about my line?
This was a pot odds call, and his big bet looked more like a bluff than a valuebet to me. How often am I ahead at river?