Green Bay took the opening drive 58 yards for a touchdown, and the first score of the game. The remainder of the Packers' drives in the first half were largely unsuccessful. On the first play of the second quarter, Aaron Rodgers pass was tipped and then intercepted by Derrick Brooks. The turnover set the Buccaneers up on the Packers 32-yard line. Shortly thereafter, Brian Griese connected to Alex Smith to tie the score at 7. Later in the second quarter, Green Bay faced 4th & 15 at their own 5-yard line. Derrick Frost punted from the back of the endzone, but the punt took a "Buccaneer bounce" and was downed at the Green Bay 41-yard line. The resulting good field position led to a Matt Bryant field goal, and a 10-7 lead. Earlier in the week, Bryant suffered tragedy off the field, with the death of his 3-month old son Tryson. Four plays later, Rodgers was intercepted again, this time by Barrett Ruud. Before the end of the second quarter, Bryant kicked another field goal, and the Buccaneers led 13-7 at halftime. Tampa Bay took the second half kickoff, and drove to the Packers 17-yard line. A play later, however, Griese's pass was bobbled by Michael Clayton at the 5, and intercepted by Tramon Williams. After trading possessions, midway through the third quarter, Green Bay was at their own 40-yard line. Ryan Grant fumbled, and Jermaine Phillips recovered for a 38-yard Buccaneer touchdown. On the second play of Tampa Bay's next drive, Griese threw his second interception, which was returned to the 42-yard line. Aaron Rodgers threw a 48-yard touchdown pass to Greg Jennings to trim the score to 20-14. Rodgers, however, appeared to injure his throwing arm on the play. Early in the fourth quarter, Griese threw his second straight interception (and third overall), which was returned 62 yards by Charles Woodson for a touchdown. The Packers took a 21-20 lead with just under 14 minutes to go, while rookie back-up quarterback Matt Flynn took over for the next drive. With just over 8 minutes remaining, Griese led the Buccaneers on a 10-play, 58-yard drive, capped off by Matt Bryant's third field goal, and a 23-21 lead. Green Bay started with 2:26 remaining. On the drive's second play, Rodgers was intercepted by Gaines Adams. Earnest Graham iced the game with a 47-yard rush, followed by a 1-yard touchdown.

Based on the above article, answer a question. How many points were the Packers trailing by at halftime?
6