Touching on our assets, we are very well positioned. We have assets to fit, work well together, connecting prolific supply bases to the key market hubs, with proven growth in and around our operating footprint which now, as Rick indicated, is approximately $6 billion in investments in the partnership planned through 2015, and a $2 billion-plus backlog of unannounced projects. We also have a demonstrated ability to create value for our investors and customers.
What we've got three primary business segments at ONEOK. ONEOK Partners, of course, provides the non-discretionary services that I indicated earlier to our producer, processors and customers generating predominantly fee-based earnings and significant cash to ONEOK. The distribution segment provides value by generating and anchoring our investment grade credit rating. The execution of right strategies over the past few years have led to an increase in sustainable earnings and close the gap between actual and allowed returns on equity. Our Energy Services segment adds value by providing utilities with secure and reliable supplies of natural gas.
At ONEOK Partners, our integrated operations connect prolific supplies to key markets, and as you will see later, we continue to expand our operations into growing areas of supply, and we'll talk a bit more about some of the shale plays here in a moment.
Our earnings at the partnership, as I indicated earlier, are predominately fee-based and have range between 50% and 68% since 2007, and we have a financially strong and supported general partner in ONEOK, which sounds more than 43% of our outstanding units.This map really tells the story before you hear. We are active in a number of prolific shale plays across the U.S. In particular the Bakken Shale in the Williston Basin in North Dakota has provided us with a number of opportunities to develop both, natural gas and NGL-related infrastructure and as well crude oil. Read the rest of this transcript for free on seekingalpha.com