A graph's legend represents the data presented on the graph's Y-axis, commonly known as the graph series. This is data from the columns of the associated grid report that often indicates metrics. A graph legend is often shown as a box to the right or left of your graph. It usually contains four items: a label for the series, an indicator for whether the series is increasing or decreasing, an identifier for the company that produced the data, and sometimes a statistical calculation such as "up from last year." Do not confuse a graph's legend with the axis labels you may see listed in the upper-right corner of a chart. Those are called title blocks and they contain information about the variables used in creating the chart. A graph's legend is always contained within the border of the plot area and it describes different series found within the grid report corresponding to the chart. The term "legend" also refers to the entire section containing all the series information for a chart. You can manipulate this section via the API or through other code by using the ChartDataService class. For example, let's say you have a line chart that shows sales revenue over time.