A business had the following accounting figures for $2015$:

Material dept. Production dept. S$/$A department

Direct material costs NOK $100,000$

Direct salary costs NOK $250,000$

Indirect variable costs NOK $50,000$ NOK $50,000$ NOK $200,000$

Indirect fixed costs NOK $50,000$ NOK $100,000$ NOK $200,000$

The activity target in the Materials Department is direct materials, while in the Production Department it is production hours, which was $1,000$ hours last year. The activity target for Sales and administration costs is Production cost. The company uses the self$-$cost principle in its calculation.

What was the additional rate for the Materials Department?