Sure. There are a number of different candidates. We originally chose CPIX because it was a way to measure a core that we focus on most, that excludes volatile items. What we've seen over the last couple of years is that the usefulness of this measure as an operational guide—we can see through the volatility and the total CPI index and set monetary policy to see through that so we don't change interest rates for something that will be over by the time it has an affect. That's what we're doing.
The usefulness of that has declined for a number of reasons, which we've talked about in research that's been published. So we're looking at other measures. Some of them are highly statistical measures that use more complex econometric techniques. We're also looking at measures that crop.... Instead of excluding the same items every time, they crop the items that increase the most and those that increase the least in any particular period, in doing statistical tests to see which ones perform the most, the best, and will serve us well. That research is ongoing but a lot of it's on our website, if you want to have a look.