How to display how many process complete asynchronously in asp.net mvc?

public JsonResult DoProcess(List<string> data)
    {
        foreach (string str in data)
        {
            try
            {
                System.Threading.Thread.Sleep(2000);// process
                complete++; //global variable initialize with zero.

                if (complete == data.Count)
                    isComplete = true;

            }
            catch (Exception ex)
            {
                var error = new ErrorList
                {
                    ErrorMessage = ex.Message
                };
                complete++;
                if (complete == data.Count)
                    isComplete = true;
                errors.Add(error);
            }
        }
        return Json(errors);
    }