A sparkline is good for displaying and comparing one or more categories of data, and is often used to display data across a time period. It's similar to a line chart, but displays data lines on separate axes stacked on top of each other.
Check out an example of a sparkline.
Data format
Each column of the spreadsheet should contain numeric data, and there's no limit to the number of columns that can be displayed in the sparkline. Labeling each column in the spreadsheet will allow you to track your data more easily; these labels will also appear on the chart.
Learn how to customize your chart.