Merjenje proizvodnje je pred tem temeljila na konceptu "nacionalne kmetije", enega samega imaginarnega kmetijskega gospodarstva, ki je opravljalo vso kmetijsko proizvodnjo nacionalnega gospodarstva, pri čemer je bila proizvodnja vsota vseh proizvodov, ki so zapustili nacionalno kmetijo.
The measurement of output was previously based on the concept of the "national farm", a unique, notional agricultural holding performing all the agricultural production in a national economy, agricultural output being the sum of all products leaving the national farm.