"Yr" is a shorthand or abbreviation for the word "year." It is often used in informal written communication, such as text messages or online chats, to save time and space. Full definition
I am a doctoral level therapist with 20 + yrs of experience. (theravive.com)
I have some old — like almost 20 yrs ago old, due to a bad medication... no problems since, but keeps me from getting a good affordable policy. (abramsinc.com)
I wouldn't be surprise if its one of the few electrical bits on your 50 + yr old car that still works. (mechanics.stackexchange.com)