C. The increase of values which industry[146-3] and commerce add to the first two classes up to the time of their final consumption.
D. Services in the narrower sense and the produce (Nutzungen) of capital in use.
All these several elements, estimated at their average price in money, which supposes that all purchases, especially those under the head D, are made voluntarily[146-4] and at their natural price.
To find the national net income, we must deduct the following items:
A. All the material employed in production which yields no immediate satisfaction to any personal want.[146-5]
B. The exports which pay for the imports.
C. The wear and tear of productive capital and capital in use.
In the second case the net national income is to be calculated from the following items:
A. From the net income of all independent private businesses etc.[146-6]
B. From the net income of the state, of municipalities, corporations and institutions, derived from their own resources.