After assessing well completion and production data from IHS Global Insight and DrillingInfo Inc., EIA found that:

In 2000, approximately 26,000 hydraulically fractured wells produced 3.6 billion cubic per day (Bcf/d) of marketed gas in the United States, making up less than 7% of the national total. By 2015, the number of hydraulically fractured wells had grown to an estimated 300,000, and production from those wells had grown to more than 53 Bcf/d, making up about 67% of the total natural gas output of the United States.

In other words, since 2000, the amount of natural gas unlocked by fracking has increased by more than 1,300 percent.

Of course, the Barnett Shale here in North Texas has been a significant contributor to this shift. 

Since 2003, the Barnett Shale has produced more than 15 trillion cubic feet of natural gas, enough to heat 225 million homes for an entire year. Furthermore, the U.S. Geological Survey estimates that there is an additional 53 trillion cubic feet of recoverable gas resources remaining in the formation.

Earlier this year, EIA reported that fracking is also responsible for half of all oil production in the United States.