From 1975 to 1993, Mexico issued a series of definitive regular and airmail stamps in a uniform style depicting a great variety of products Mexico exports, such as beef, bicycles. tomatoes and chemicals, each stamp bearing the Exporta Logo. The series was added to over the years, and there are a great number of variants of papers, sizes, colors, watermarks, and plate flaws. A number of the stamps had burelage printed on their surface. Specialists have also identified 14 different weights and grades of paper used on the stamps. As a result of the collecting challenges, the Exporta issue has received a great deal of attention by collectors and is the most popular modern series.