The Cowboys slugged the Tampa Bay Buccaneers 38-10 in the annual Thanksgiving Day game.  Tony Romo had his best game so far throwing for 306 yards and a near-perfect 148.9 passer rating, and he tied a team record with five touchdown passes in one game. No Cowboys quarterback had done that since Troy Aikman in the 1999 season opener (including overtime), and since Danny White in 1983 in regulation. Romo's five touchdown passes were the most ever for a Thanksgiving Day game. Stats On 27 November 2006, the Cowboys cut kicker Mike Vanderjagt and signed veteran Martin Gramatica in his place. Vanderjagt had made only 13 of 18 field goals in the season, well below his career average.
Question: How many field goals did Vanderjagt attempt on the season?
Answer: 18