As of the end of September, the Dow has only had one down month in the last 12. If the market closes the end of October where it is today, the Dow would have risen in 12 out of the last 13 months. For a look at how this compares to history, below is a table of other big Dow monthly gain streaks that were only interrupted by one down month. I'll dub these 1 hitters--almost perfect games but gave up one month in the middle of a hot streak.
There are only 4 other occurrences in 112 years that the Dow has had a longer one-hit streak than the current one.