A forecasting model has produced the forecasts as follows: For the period of January, the demand is $120$and the forecast is $110.$For the period of February, the demand is $110$and the forecast is $115.$For the period of March, the demand is $115$and the forecast is $120.$ For the period of April, the demand is $125$and the forecast is $115.$ For the period of May, the demand is $130$and the forecast is $125.$What is the mean absolute deviation $($MAD$)$ for the end of May?