Ohh I see now, @CreationsOfaNoob
In Swedish orthography, the colon is used in a similar manner as in English, with some exceptions: the colon is used for some abbreviations, such as 3:e for tredje ("third") and S:t for Sankt ("Saint"), and for all types of endings that can be added to numbers, letters and abbreviations, such as a:et ("the a") and CD:n ("the CD"), or the genitive form USA:s ("USA's").
I noticed you use colons for 1st, 2nd, 3rd but didn't think much about it; now I see — I did not know this at all!
I was just curious about the origins of the Swedish language (e.g. languages classified as Romance languages have histories in Latin as an example, and I was wondering about Swedish) and happened to come across this.