Forecast in QS

Hello, I would like to have some forecast, based on two count of the last two, three years.

I have years 2015 count 890

                    2016 count 1050

                    2017 count 1065

Now can I estimate count for 2018 basid on some function in qlik (regression or something else)?

I already know that there are function as LINEST, but how I should write the formula?

Thanks for any helps.