The officially reported labor force, which comprises nonagricultural labor and state farm workers only, increased by 53 percent between 1960 and 1967, from 203,800 to 312,400 persons. The increase represents an annual growth rate of 6.3 percent. At this rate, the labor force in 1970 would be about 375,000 persons. It has been informally reported as 400,000. Collective farm employment rose, in round numbers, from 282,000 in 1960 to 336,000 in 1966 and to 427,000 in 1967. The unusually large increase in 1967 resulted from an intensive drive to collectivize the remaining privately owned farms and also from a government policy of reversing the population flow from the farms to the cities. With the major reservoir of individual farms exhausted, the number of collective farm workers could increase up to 1970 by roughly 45,000 to 50,000 through natural population growth. Absence of data on rural-urban population shifts precludes any firm estimate of the size of the collective farm labor force in 1970. According to preliminary estimates by the planning authorities, an increase of between 120,000 and 130,000 workers outside the collective farm sector would be needed to implement the industrial and social programs of the five-year plan for the 1971-75 period if productivity remained at the level of the 1965-69 period. The natural growth of the able-bodied urban population during this period was estimated not to exceed 29,000 persons. An outflow of up to 100,000 persons from the rural areas would therefore be necessary to meet the estimated manpower needs. Such a contingency could not be countenanced because of the severe damage it would inflict on the rural economy. Attainment of a higher rate of participation in the labor force and of a substantial increase in labor productivity has therefore been considered by the Party leadership of utmost urgency to ensure sustained economic development. The latest evidence of the leadership's profound concern about these basic labor problems was provided by the Party's Central Committee plenum held at the end of December 1969, devoted to a discussion of means for raising productivity and tightening labor discipline. In its report delivered to the plenum, the Political Bureau (Politburo) of the Central Committee expressed strong dissatisfaction with what it considered an unsatisfactory rate of participation in employment by the collective farm population. It placed the blame for this situation on local government organs, which had become reconciled to the backward traditional concepts that keep homemakers and some young girls in the home and that require a member of the family to look after the family's privately owned livestock and thus be unable to seek outside work.