Iguana Company sells a single product. Iguana estimates demand and costs at various activity levels as follows: Units Sold Price Total Variable Costs Fixed Costs 120,000 $48 $3,000,000 $1,000,000 140,000 $45 $3,500,000 $1,000,000 160,000 $40 $4,000,000 $1,000,000 180,000 $35 $4,500,000 $1,000,000 200,000 $30 $5,000,000 $1,000,000 How would you best describe Iguana's variable cost per unit over the range shown?