Data - Time Series Plot
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You need one or more columns of time series data in chronological order. You may also use up to three columns of categorical data for grouping. For multiple overlaid time series with groups, all columns (series and grouping variables) must be of equal length.

To use a stamp for x-axis labels, you need one to three columns of numeric, text, or date/time columns. See Time overview.

If data in your series are missing, those worksheet rows must contain missing values in order to maintain the proper spacing in the time scale.