Since it was I who put you up to this ... There is a spreadsheet made available by IJM for checking linearity, which has a tab for luminosity data and one for density data. However the density tab has hidden columns that take the density data and convert it to luminosity and plot that rather than density, because the ideal QTR curve is linear in luminosity.
When I plot your data in the density tab of that spreadsheet the linearity is pretty good, as Walker said. Perhaps a touch light in the shadows. Someone who is ultra critical might do a second linearisation. I'm not sure I'd bother in this instance.
Spreadsheet here: https://inkjetmall.com/blog/blog/checking-your-linearization/