monthly sales number of dealerships 1st quarter (1 if jan.-mar., 0 otherwise) 2nd quarter (1 if apr.-jun., 0 otherwise) 3rd quarter (1 if jul.-sep., 0 otherwise) 4th quarter (1 if oct.-dec., 0 otherwise) 85420 3 1 0 0 0 101390 10 1 0 0 0 121318 13 1 0 0 0 133663 16 1 0 0 0 194508 22 1 0 0 0 82127 3 0 1 0 0 150425 10 0 1 0 0 242709 13 0 1 0 0 260395 16 0 1 0 0 273419 22 0 1 0 0 65420 3 0 0 1 0 101446 10 0 0 1 0 150147 13 0 0 1 0 165498 16 0 0 1 0 200404 22 0 0 1 0 98549 3 0 0 0 1 200398 10 0 0 0 1 250192 13 0 0 0 1 306507 16 0 0 0 1 389511 22 0 0 0 1
