Over the last decade or so, a "stealth bull market" has developed for better Latin American material, especially for scarce issues with wide topical appeal. Supplies have been gradually depleted, and many items which formerly retailed for about 20%-30% of Scott are now selling for 60%-80%, and their catalog values have substantially increased as well. Frequently, Michel Values, which are usually much higher than Scott for Latin America, are used by auction houses when listing this material. As the region has cast aside its authoritarian dictatorships and become more democratic, it has experienced healthy economic growth and the concurrent development of a middle class.
El Salvador, a nation of 5.7 million, is a poor though steadily developing economy, which has experienced annual GDP growth averaging 3.5% over the last 5 years. In addition, there are between 500,000 and 1 million Salvadorans in the U.S., most of whom immigrated during El Salvador's "Dirty War" of 1979-92. Salvadorans in the United States are among the hardest-working immigrants, and send about $800 million back to their families in El Salvador every year. Although Salvadoran Americans toil in the lowest-paying sectors of the American economy, they are slowly but inexorably becoming more prosperous. They work long hours, save a great deal, and are gradually entering the middle class.
While I believe it may take a while for a significant stamp collecting population to develop among Salvadorans, this is mitigated by the fact that many collectors of Latin American stamps collect the region generally, rather than specializing in a particular country. Furthermore, the Eucharistic Congress issue is a Religion topical which may appeal to Catholic collectors worldwide, many of whom live in emerging market nations.