A team has finished a game with 18-9 singles and extra-base hits 1 time since 1897, most recently New York Giants on 10 September 1924. That is about one every 443,004 team-games.
Box score for the most recent one ↗
18-3 18-4 18-5 18-6 18-7 18-8 18-9 18-10 19-0 19-1 19-2 19-3 19-4
The whole distribution — Singles and Extra-Base Hits · All 18 shapes