Forecasting

[Hollyoak08]

Hi, I have a table that consists of data from sales. My table looks like this
Year Year Year Year
Month (Value) (Value) (Value) (Value)
Month (Value) (Value) (Value) (Value)
Month (Value) (Value) (Value)
Month (Value) (Value) (Value)

I need to predict the final values how do I go about this

[JBeaucaire]

Perhaps comparing the trend would give a useful guess.