Energy Information Administration (EIA) Storage Data
Natural gas stocks are an important indicator of natural gas supply and demand conditions. Working gas in storage is one of the few timely indicators of the relative scarcity or abundance of gas in the market.
This chart represents storage levels starting with the injection season on April 1 and the withdrawal season on November 1 each year.
For current gas storage, visit: http://ir.eia.gov/ngs/ngs.html