The NBA In-Season Tournament is down to the semifinals, and the Indiana Pacers and Milwaukee Bucks play on Thursday night in what Vegas expects to be one of the highest-scoring games in decades. In fact, the Pacers-Bucks over/under is so high (257.5), that we haven’t seen another one like it since 1991.

The Pacers and Bucks made it to the semifinals of the NBA In-Season Tournament because they are two of the highest-scoring teams in the league right now. The Pacers are the highest-scoring team at 128.4 points per game, and the Bucks are in third with 122.3.

This combined 250.7 scoring average is the second-highest in NBA history, according to the Elias Sports Bureau (h/t ESPN). The only time two teams met that averaged more combined points per game was in 1961 when Oscar Robinson’s Cincinnati Royals took on Wilt Chamberlin’s Philadelphia Warriors with a combined average of 252.3.

The Pacers-Bucks over/under at 257.5 is the highest NBA bettors have seen since 1991. In March of the 1990-91 campaign, Paul Westphal’s run-and-gun Denver Nuggets took on Don Nelson’s “Nelly Ball” Golden State Warriors, and the over/under was 259. Golden State won the game 136-113, missing the over by 10 points.

The Bucks are -5 favorites to win this game and move on to the In-Season Tournament Final. The winner of this game will face the winner of the Los Angeles Lakers vs. New Orleans Pelicans game, where the Lakers are -2 favorites (and the over/under is “just” 231).

The final game of this first-of-its-kind NBA tournament will take place on Dec. 9.