Plot quarterly and annual data on same graph in gnuplot

I need to plot two time series on the same graph. One series has annual observations, while the other series has quarterly observations. Is there straightforward way to do this?

The only solution I have come up with is to expand th开发者_C百科e annual data by repeating each year's observation four times, but I'm wondering if there is a way to do this within gnuplot instead of by editing my data.

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Quarterly plots in gnuplot are not supported. (check this link).
Maybe you can restructure your data to plot a time series with each point representing a year and another time series where each points represents a month?

I fiddled a little around with two time series (one containing yearly the other containing quarterly data) but could not find a satisfying solution. I am looking forward to other responses.