A concert promoter is forecasting this year's attendance for one of his concerts based on the following historical data:YearAttendanceFour Years ago$10,000$Three Years ago$12,000$Two Years ago$18,000$Last Year$20,000$ What is this year's forecast using exponential smoothing with alpha $=0\mathrm{.}2,$ if last year's smoothed forecast was $15,000?$