Theme release year

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varerc Theme release year is the year that a theme is officially (if consulting LEGO) or generally (if talking amongst ALEs) considered to have been first commercially available. This can be a subject of some controversy sometimes, as some themes are old enough that it is not clear when they were first released (what is the first year of System, for example?), and some newer themes are released at different times in different markets, or previewed one year but released early the next. "January" themes are nowadays usually released in December of the previous year in some markets. Sometimes the difference turns on whether something was intentionally sold rather than accidentally, as there have been instances of inadvertant releases of merchandise.