Any of your Daily, 15 Min. Interval, and Monthly graphs support the ability for you to download the data used to display that graph through the web client.
In the toolbar, on the left-hand side of each graph, the Export icon is listed third from the top. Select that icon, and you will immediately download an electronic Comma Separated Value file (CSV). Microsoft Excel and Notepad are common applications used to read CSV files. Only the data you are currently displaying or overlaying on the graph will be included in the download.