Your dividend yield sometimes differs from other sites, how do you calculate it?

Stock Rover calculates the dividend yield by dividing the forecasted yearly dividend payout by the current price. For example, in the case of Terra Nitrogen Company (TNH) using data from November 6th, 2013, the last quarterly dividend payment was $2.02, so the forward dividend yield is (4 * 2.02)/198.76 = 4.1%. The forecasted yearly dividend payout is listed in Stock Rover in the Dividends Per Share metric.

It is possible that the other sites are calculating dividend yield using a trailing dividend value, causing the difference between their values and ours.