During a year, Mark's monthly sales compensation ranged between $19,500 and $26,500 per month and units sold ranged between 1,400 and 2,200 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 $235,750. (Round your "Commission rate" to 2 decimal places.)