Compare multiple series
Use the input box next to the "add data" button to search and add additional data series into the same graph. If you add a monthly series to a yearly time series, the monthly series will be converted to yearly automatically either as a sum (for accumulative data such as auto sales) or as an average (for non-accumulative data such as unemployment rate.)
Data mashup
You can use simple arithmetic operations to create any custom data series of interest to you. Each data series in your view is referenced alphabetically starting from A, B, C and so on. For instance, suppose you have two data series in your view, then the 1st data series is A and the 2nd data series is B. Inputting the expression
A / B will produce the ratio between the 1st and 2nd data series. You can easily extend this to contruct any mashup of multiple data series.
