How to control the size of the plot inside the figure in matplotlib

Please see attached graph. There are only two items on the x-axis, yet it takes the whole space. I like to leave some blank on each side so that the actual graph only fills 25% to 75% of x axis. I am not exactly sure keyword in matplotlib controls that.

To be clear, I want Last Year around 25% of x axis and This Year around 75% of x axis. Thanks.

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