estimated to be more than $200 per barrel of oil equivalent (UK North Sea oil prices were about $120 per barrel in April 2012). However, no cost figures were made public for onshore shale gas. North America has been the leader in developing and producing shale gas. The economic success of the Barnett Shale play in Texas in particular has spurred the search for other sources of shale gas across the United States and Canada, Some Texas residents think fracking is using too much of their groundwater, but drought and other growing uses are also part of the causes of the water shortage there. A Visiongain research report calculated the 2011 worth of the global shale-gas market as $26.66 billion. A 2011 New York Times investigation of industrial emails and internal documents found that the financial benefits of unconventional shale gas extraction may be less than previously thought, due to companies intentionally overstating the productivity of their wells and the size of their reserves. The article was criticized by, among others, the New York Times' own Public Editor for lack of balance in omitting facts and viewpoints favorable to shale gas production and economics. In first quarter 2012, the United States imported 840 billion cubic feet (Bcf) (785 from Canada) while exporting 400 Bcf (mostly to Canada); both mainly by pipeline. Almost none is exported by ship as LNG, as that would require expensive facilities. In 2012, prices went down to US due to shale gas. A recent academic paper on the economic impacts of shale gas development in the US finds that natural gas prices have dropped dramatically in places with shale deposits with active exploration. Natural gas for industrial use has become cheaper by around 30% compared to the rest of the US. This stimulates local energy intensive manufacturing growth, but brings the lack of adequate pipeline capacity in the US in sharp relief. One of the byproducts of shale gas exploration is the opening up of deep underground shale deposits to "tight oil" or shale oil production. By 2035, shale oil production could "boost the world economy by up to $2.7 trillion, a PricewaterhouseCoopers (PwC) report says. It has the potential to reach up to 12 percent of the world’s total oil production — touching 14 million barrels a day — "revolutionizing" the global energy markets over the next few decades." According to a 2013 Forbes magazine