Plotting only every Nth point

I'm plotting data as yWave vs. xWave. There are simply too many points displayed. I'd like to only plot every, say, 10th point. But I don't want to delete any of the data.

Also, I use several different yWaves---something like yWave1, yWave2, etc---plotted against the same xWave, so I don't want to have to change the values of xWave.

Thanks,
Kevin