In the 2008 MLB season, the average runs scored per game in a National League game was 9.08 and in an American League game was 9.56.
The MLB and National League record for runs scored by a team in an inning is 18 by the Chicago White Stockings in the 7th inning of a game against the Detroit Wolverines in 1883. The American League record is 17 by the Boston Red Sox in the 7th inning of a game against the Detroit Tigers in 1953.
Once the Red Sox scored 17 points in one inning.
Only a handful of times (I think onlty 3 or 4) has a player scored at least one run in all 9 innings, and in none of them did they score exactly one run in each inning. So, no.
I am a bloke but, I recall hearing somewhere that is was 5 to 3. But I have no more authority than that. ---- In the 2007 season, the average runs scored by a National League team was 471.78 and an American League team was 122.87. In 2006, the NL average was 4.76 and the AL average was 4.97.
30, scored by the Texas rangers
Usually it's the ninth inning because that's when teams rally from behind.