<P> The series consists of a number of individually themed collectible Lego minifigures based on movies, sports, history, and popular culture . The figures are sold individually in sealed, unmarked packages, giving customers a random chance at obtaining any particular figurine . While considered a novel approach by some, it has raised controversy amongst enthusiasts and collectors, increasing the amount of difficulty in obtaining a complete collection . Purchases from many retailers make no guarantees regarding the contents of a particular package . Despite attempts to obfuscate the contents of these packages, the bags of Series 1 and 2 have a second figurine - specific bar code on the rear of the packaging, next to the EAN / UPC product bar code (which is unique to each series). This has allowed customers to identify individual figures within the packaging, significantly decreasing the amount of money and effort required to obtain a complete collection, and eliminates the possibility of unintentionally receiving duplicates . There are also apps for both iPhone and Android devices that utilize these bar codes . </P> <P> Lego has eliminated the figurine - specific bar codes on all Series 3 and 4 packages and replaced them with a braille - like system of dots embossed in the lower seal of the bag . In theory, this will allow customers to continue identifying the figure enclosed within . Later series do not have any markings to indicate their contents . </P> <P> On average a new series has been released every four months . Release dates sometimes vary between countries . </P> <P> Series 1 (set number: 8683) was first released on March 5, 2010 in the United Kingdom and was released on June 4, 2010 in the United States . The first series consists the following units: </P>

How often do lego minifigures series come out