Looking at the universe of stocks we cover at Dividend Channel, in trading on Monday, shares of NiSource Inc. ( NI) were yielding above the 3% mark based on its quarterly dividend (annualized to $1.00), with the stock changing hands as low as $33.21 on the day. Dividends are particularly important for investors to consider, because historically speaking dividends have provided a considerable share of the stock market's total return. To illustrate, suppose for example you purchased shares of the S&P 500 ETF (SPY) back on 12/31/1999 — you would have paid $146.88 per share. Fast forward to 12/31/2012 and each share was worth $142.41 on that date, a decrease of $4.67/share over all those years. But now consider that you collected a whopping $25.98 per share in dividends over the same period, for a positive total return of 23.36%. Even with dividends reinvested, that only amounts to an average annual total return of about 1.6%; so by comparison collecting a yield above 3% would appear considerably attractive if that yield is sustainable. NiSource Inc. ( NI) is an S&P 500 company, giving it special status as one of the large-cap companies making up the S&P 500 Index.In general, dividend amounts are not always predictable and tend to follow the ups and downs of profitability at each company. In the case of NiSource Inc. , looking at the history chart for NI below can help in judging whether the most recent dividend is likely to continue, and in turn whether it is a reasonable expectation to expect a 3% annual yield.