AM AS our elders might have said, food for thought. Honest, diligent statisticians are at work, and they produce honest, diligent statistics. Such that, in the fifteen years since 1970-71, real income in the country's primary sector, consisting of agriculture and allied activities as well as of mining and quarrying, has grown at the rate of around 2 per cent per annum, and the corresponding rate of advance in the secondary sector, comprising manufacturing, electricity, gas and water supply, and construction, has been a little above 4 per cent per annum. The real buoyancy, we have been informed, is however in the nation's tertiary sector