quality:correction, stylistic:style_transfer, structural:expansion, information:classification, information:filtering
Norway and Finland

Norway and Finland changed their national identification numbers to indicate a person's century of birth. In both countries, the birth year was historically indicated by two digits only. This numbering system had already given rise to a similar problem, the " Year 1900 problem ", which arose due to problems distinguishing between people born in the 19th and 20th centuries. Y2K fears drew attention to an older issue, while prompting a solution to a new problem. In Finland, the problem was solved by replacing the hyphen ("-") in the number with the letter "A" for people born in the 21st century (for people born before 1900, the sign was already "+"). In Norway, the range of the individual numbers following the birth date was altered from 0–499 to 500–999.