Here's the good news for the Boston Red Sox and Philadelphia Phillies: They've managed to shake off dreadful starts and build their records back to .500. The bad news? Entering Wednesday, they were still in last place.

All 10 teams in the American League East and National League East began the day with records above .500. No division has ever finished that way after a full season since divisional play began in 1969. Only twice has a division had all of its teams finish at .500 or better, which raises this question: If one of this year's Easts keeps it up, would it be baseball's best division of all time?

Depends on how you look at it. The NL East had a combined winning percentage of .550 entering Wednesday, while the AL East was at .544. Those figures are substantially better than the 2005 NL East (.525) and 1991 AL West (.526)—the two divisions to finish the year with all of its teams no worse than .500.

The 2002 AL West holds the record for the best overall winning percentage for a division (.566), but that figure is inflated by the fact that it only had four teams. Oakland, Anaheim and Seattle all won at least 93 games that year.

By another measure, the 1991 AL West is the best ever, since it had seven teams finish at or above .500. In that regard, the AL East in 1979 and 1981 also rank highly, with six of seven teams winning at least as many as they lost.