Something like 40 per cent of the Paraguayan economy depends on smuggling, but there is no mention of that anywhere in any official economic documents. It would be too embarrassing to the officials everyone assumes to be up to their wallets in it themselves.

Similarly, official census figures in Uruguay never hint that the official 1975 population of 2.8 million (only about 10,000 more than shown in the 1963 census) actually represented a sharp drop in the previous two years. It is estimated that half of million uruguayans - a sixth of the population - emigrated after 1973 for political and economic reasons. Obviously, the government does not want to mention that.

Everywhere in Latin American statistics on such economic factors as unemployment, foreign investment, crop estimates and the military budget carry too much political freight to be bandied about freely. They are routinely high or low, creatively broken down into novel categories, or simply not made public. The problems for international number-gatherers are awesome.

"We use official figures, but if you read the analyses closely we usually manage to hint what the delicate areas are," said Eric Calcagno of the Buenos AIres office of the United Nations Economic Commission of Latin America.

Unemployment and tax-payment rates are notoriously the most unreliable; national budgets are rarely considered to be much more than wishful thinking.

The few exceptions include Venezuela and Brazil, both of whose economies are strong enough to be bragged about. Even there, however, most diplomats feel that the number of desperately poor and the rate of illiteracy are understated.

Military budgets are almost universally secret, and where they are not the official figures fail to include arms purchases, as in Peru, or list only about half the actual spending as in Ecuador.

No government likes to admit that smuggling or illegal narcotics trade is a pillar of the economy, but that is sometimes the case. Peasants in rural Peru and Bolivia have converted subsitence farms to thriving producers of coca leaves, the raw materials for cocaine. Most of the leaf production is blantantly illegal, but authorities admit that the peasnats would go huntry and the rural economy would stagger if it were wiped out.

Whole towns along virtually all the borders in the continent make their living by smuggling. The cargo ranges from lipsticks through electronic equipment to live animals and truckloads of grain.

About 300,000 steers walk into Venezuela every year from Colombia, where prices are lower, supplying about a fifth of Venezuela's beef consumption.Argentina's entire 1975 soybean crop was trucked across to Paraguay, where it did not appear on the books.

A two-car electric train between Africa, Chile, and Tacna, Peru, carries mainly the "packettterss" or small-time smugglers, according to the Tacna customs officers. "Well, it isn'tt' very much and they're none of them rich," shrugged one guard.

Of course, his livelihood may depend on his cut, and the job of a border guard is not easy. Only two roads cross from Bolivia to Brazil, for example, one at either end of the 1,400-mile jungle border. Travelers report that the guards there are quite open aa a a bout accepting their shares.

The difficulties of official obfuscation are compounded by the use of official currency exchange rates, often wildly out of line with real costs and income, in statistical tables.

During the worst inflation in Chile, in early 1973, a room at the luxury-clclclcass Sheraton-Cristobal Hooel in Santiago officially went for escudos worth $50, and that wasss what was reported. But travelers chaning money on the black market spent $5, and that was the hotel's real income.$

Some diplomats say the onlyy time they fully trust government figures is just after a coup, and even then they make some adjustments for politics. Argentina's new military chiefs revealed a year ago that the 1976 inflation level would have been 6,000 per cent if it had continued at pre-coup rates that had been kept secret. Puru's new President Francisco Morales Bermudez discovered a "serious crisis" in the economy that his predecessor had denied.

Between coups, reliable statistics continued to be elusive as the thousands of emerald-smugglers who officially do not exist in Colombia. An informant in Bolivia once asked to be paid for a particularly tantalizing bit of data; the true size of the national debt. It remains a closely guarded secret.