Baker Hughes released their well count data for Q3 2013. The report counts well spuds by basin, as well as average rig counts. It does not distinguish between oil and gas, which reduces usefulness.
But the dry gas areas can be assumed to contain primarily gas rigs, and by comparing rig count averages in these basins with well spuds, an implied average drill time can be calculated. The net result is that the big dry plays showed little if any improvement in rig efficiency: