MATLAB: Add units to colorbar TickLabels (format)

I'm trying to add percentage signs to TickLabels in colorbar

Here's my code:

 contourf(peaks)
 c = colorbar;
 c.TickLabelFormat =  '%g%%'

yet the next message appears: "No public property TickLabelFormat exists for class matlab.graphics.illustration.ColorBar"

I know you can set the scale value with symbols manually as it's explained here:

https://www.mathworks.com/help/matlab/creating_plots/change-colorbar-width.html

but I would like add the symbol to any value the colorbar takes. It should look like this:

I would really appreciate any help you could give me. Thanks!