Here, we describe the role of natural gas in the US economy, describe the details of our data-fitting procedures, provide additional evidence concerning the correspondence of the dimensionless recovery factor (RF) and well production data, provide upper and lower bounds on gas production from wells not yet showing interference, demonstrate why production declines as the square root of time early on and exponentially later, and tabulate the coefficient κ for a variety of reservoir and well flowing pressures to  demonstrate how little it varies. In a separate spreadsheet (Dataset S1), we provide tabulations of the dimensionless RF.