Draws/Goals per game
This is the number of games tied after 90 minutes, which is the fair way to compare the games from all years. With 21 games to go this season, It's no surprise that the percentage has dropped. RSL and Chivas are just so horrible, and you also have San Jose and New England who are great teams. I don't know if I would've predicted a 9% drop though. Next year, I would guess it goes back up to around 25%, which is still pretty low.
Also, notice how it was high the two years before they eliminated the shootout and overtime (1999 and 2003).
Draw percentages for most leagues around the world (2003-4 season), thanks to Bigsoccer's Elninho.
Goals per game (this does include overtime goals, BTW). 1998 was the year where DC and LA destroyed the competition. Generally, the more even a league is, the more draws and fewer goals they have. Most leagues are in the mid to upper 2.00's, so the last few years are what we should expect in the future, not the high scoring of the first few years. Expansion caused a rise this year because the player pool was expanded this year. The level of play should be better in 2006. I would expect a slight decrease next year. Not too much, because RSL and Chivas should have better offenses. Their defenses can't get much worse.