I would like to create a bar plot with two x-axis, one for the months and another for the year as shown in the picture below. I tried to find examples but couldn't find any and I don't really know where to start.
Any help is welcome.
You can call x-axis as many times you want. As illustrated in this link you can call it multiple times. For using separate tick values, this link explains year / month tick formatting for axes. Hope these will help.