Circuit breaker levels for the NYSE

The Market opened this morning and was immediately way down. Yahoo finance briefly showed a drop of 1,000 points, but quickly updated their page (and I didn't get a screenshot). Google finance shows the swings so far today (in the first hour of trading) to be above 800 points. With movement like this, it's time to ask when they put the breaks on. A quick search led me to a blog post from the Financial Times:

Circuit-breaker points represent the thresholds at which trading is halted marketwide for single-day declines in the Dow Jones Industrial Average (DJIA). Circuit-breaker levels are set quarterly as 10, 20 and 30-percent of the DJIA average closing values of the previous month, rounded to the nearest 50 points.

In fourth-quarter 2008, the 10, 20 and 30-percent decline levels, respectively, in the DJIA will be as follows:

Level 1 Halt
A 1,100-point drop in the DJIA before 2 p.m. will halt trading for one hour; for 30 minutes if between 2 p.m. and 2:30 p.m.; and have no effect if at 2:30 p.m. or later unless there is a level 2 halt.

Level 2 Halt
A 2,200-point drop in the DJIA before 1:00 p.m. will halt trading for two hours; for one hour if between 1:00 p.m. and 2:00 p.m.; and for the remainder of the day if at 2:00 p.m. or later.

Level 3 Halt
A 3,350-point drop will halt trading for the remainder of the day regardless of when the decline occurs.

Source