BKTssä
BKTssä is a Finnish written form related to the abbreviation BKT, which stands for bruttokansantuote (Gross Domestic Product). The element -ssä is the Finnish inessive case ending meaning "in" or "within", so BKT:ssä or BKTssä is used to indicate something measured or situated "in GDP" or "as a share of GDP" (for example, public debt BKT:ssä 60 %).
In formal Finnish orthography a colon is normally inserted between an abbreviation and a case ending to
Typical usage occurs in economics, public statistics and reporting: phrases like "BKT:ssä mitattuna" (measured in GDP)