Current date format does not work in all languages

[tonimarkuk]

By using the Finnish language, this plugin cannot be used properly since it translates the dates wrong. For example, if I choose the date range of "last 7 days", it translates the start month to November ("marras") and the end month to March ("maalis"). This creates errors and results can't be shown. I guess this maybe happens because the date is written in Finnish?

Is it possible to change the date format to something with universal compatibility or at least give an option for it? The current format does not seem to come from the WordPress general settings, so I believe I have no way to change this myself.