As director of the local tourist board, you are interested in determining the factors that influence the hotel occupancy rate in your city each month. Hotel occupancy can be measured as the percentage of available hotel rooms that are occupied by paying customers. You develop the following model: Y = β0 + β1X1 + β2X2 + β3X3 + β4X4 + ε, where Y is the hotel occupancy rate, X1 is the total number of passengers arriving at the airport, X2 is a price index of local hotel room rates, X3 is the consumer confidence index, and X4 is a dummy variable = 1 during the months of June, July, and August. You look at data from the past 36 months and obtain the following results: y^ = 67.1 + 0.02x1 - 0.055x2 + 0.08x3 + 12.3x4, R2 = 0.67,  = 58.3,  = 0.008,  = 0.01,  = 0.06,  = 4.7, and SSE = 576.

 Calculate the total sum of squares.