Any time that SL Green Realty (NYSE:SLG) announces its quarterly earnings, it's usually not a question of whether the company's funds from operations (FFO) increased -- just by how much. This time, that number was 15.7%. The New York-based real estate investment trust (REIT) announced its fourth-quarter earnings yesterday and its shareholders, who have grown accustomed windfall profits by the company, were not disappointed.

In addition to the increase in FFO, there were many other positive revelations stemming from the company's earnings release. The commercial office space landlord announced that same-store net operating income of its wholly-owned properties increased by 22.3% versus the year-ago quarter and that the company's net income had increased by 26.5% on a per share basis. As an added incentive for income investors, the company raised its quarterly dividend by 16.7%. The announcement marks the ninth consecutive year that management has upped its dividend payout rate to common shareholders.

SL Green is coming off a big year in which its stock price stormed up the charts, churning out a 78% return for investors plus dividends. Using Dec. 31 as an endpoint, the stock has risen 221% from three years ago and over 800% from nine years ago. For Fools looking at a long-term investing horizon, this security has been a clutch performer. Out of curiosity, I took a look back to see if there were any prolonged periods where shareholders of this company suffered, and there really weren't any. The stock has been virtually unstoppable for the better part of the past nine years.

I believe one of the primary motivating factors for purchasing shares of this REIT is fairly simple. The majority of SL Green's office space is located in Manhattan, and last time I checked, rent wasn't getting any cheaper in the Big Apple. For its Q4, the company was able to ink average starting office rents that represented an almost usurious 28.7% increase over previously fully escalated rents. Occupancy also increased from 96.1% in Sept. 2006 to 97% in Dec. 31, 2006. These remarkable occupancy rates are a theme common among SL Green competitors Boston Properties (NYSE:BXP) and Brookfield Properties (NYSE:BPO), who also lease commercial property in the New York metropolitan area. Both REITs maintain occupancy rates of over 95% for their New York properties.

SL Green has definitely set the bar high for itself. It might not return shareholders another 78% this year, but I think outperforming the market will not be a concern. The stock has already appreciated 10% one month into 2007. The company's Q4 numbers serve as yet another reminder that this REIT can deliver the financial results necessary to back up the lavish returns to its shareholders.

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Fool contributor Billy Fisher does not own shares of any of the companies mentioned. The Fool will not hesitate to evict any and all violators of our disclosure policy.