144 PONTIFICIAE ACADEMIAE SCIENTIARVM SCRIPTA VARIA - 28 
[. AGRICULTURE AND ECONOMIC DEVELOPMENT (!) 
A. General Framework 
One of the important interrelationships between agriculture 
and the rest of the economy during the process of economic 
development has been called the law of declining importance 
of agriculture. This « law » has both very strong empirical 
support and a firm analytical base (?). The major industrial 
countries of the world, with the exception of the United King- 
dom, had at the beginning of the 19th century approximately 
the same percentage of the labor force engaged in agriculture 
as is now true in the low income countries of the world. Except 
for the Soviet Union, all of the major industrial nations now 
have 20%or less of their labor force engaged in agriculture, 
with the United Kingdom at about 5% and the United States 
at 8%. 
The theoretical analysis that explains the empirical decline 
in the relative importance of agriculture as a source of employ- 
ment as economic growth occurs is relatively simple. The 
analysis depends upon well. substantiated effects of per capita 
income changes upon the allocation of consumer expenditures 
(!) This section and certain other parts of my paper are based in part 
upon my paper, The Role of Agriculture in Economic Development, 
which was presented at the 1963 Resources for the Future Forum on the 
Role of Natural Resources in Economic Development. in Washington. D.C. 
on January 28 and 29, 1963. 
(*) The empirical support can be found in Corin CLARK, The Conditions 
of Economic Progress, 3rd ed., 1957, Ch. 10 and Simon KUzNETS, Quan- 
titative Aspects of the Economic Growth of Nations: II. Industrial Distri- 
bution of National Product and Labor Force, « Economic Development and 
Cultural Change », supplement to vol V. No. 4, July. 1057 
16] Johnson - pag. 4