Lee Manufacturing uses a standard cost system with overhead applied based on direct labor hours. The manufacturing budget for the production of 7,000 units for the month of June included 12,500 hours of direct labor at $17.00 per hour, or $212,500. During June, 6,400 units were produced, using 12,500 direct labor hours, incurring $52,000 of variable overhead, and showing a variable overhead efficiency variance of $4,200 unfavorable. What was the standard variable overhead rate per direct labor hour?