From http://seekingalpha.com/article/171794-e...

Read the rest of the article, but the first paragraph is key.

"Estimating future dividend growth is difficult if not impossible. Companies which might have had a long history of consistent double digit increases might stop raising dividends and might even cut them. It is easy to predict whether or not a company’s dividend is sustainable in the short run, by evaluating EPS trends, dividend payout ratios and cash flows. It is difficult to forecast however whether the dividend won’t be cut several years down the road."