During a typical year, Mark's monthly sales compensation has ranged between $13,000 and $17,400 per month and units sold ranged between 1,100 and 1,900 units for those same months. Required: Use the high-low method to determine Mark's monthly salary and commission rate per unit sold and then calculate the total number of units sold in a year when Mark's total compensation amounted to $141,150. Note: Round your "Commission rate" to 2 decimal places