I have a variable which is "% of a company's customers that participate in certain program" (that the company offers). Given that I have only data for past 3 years (I have month level data too for the variable) how do I forecast the next year's value ?
example - I know 53%, 54%, 52% of our customers completed a program in the past 3 years and need forecast for next year. Say the company has millions of customers. There are few variables (customer level) like a person's age, engagement, 'participation in a survey', 'contacting the company' etc. that may impact the final variable. But, on average all these customer level variables look almost same every year.
What methods (other than some sort of the average of the previous values) can I use to forecast next year variable (so from the past 36 months, I need to forecast next 12 months, and can use any customer level variables).
Methods I am looking for are not some exponential weighted averages or simple ARIMA like ( which are just basically also kind of some averaging of previous values etc.). Are there any other methods other than some sort of weighted averages methods? If possible, I am interested in methods where I can be using the customer level variables as well (I can only use some of the variables like age, "if the completed the program last year" etc. as I am looking to forecast for next year and not prediction).