AutoIt - 60 bytes
$_=@YEAR-2e3 ClipPut(($_-Round(($_-6)/4))/10+6&' 3'&3*$_-20) The rounding eats bytes. I've also simplified the formula for the US. Output for this year:
7.3 325 $_=@YEAR-2e3 ClipPut(($_-Round(($_-6)/4))/10+6&' 3'&3*$_-20) The rounding eats bytes. I've also simplified the formula for the US. Output for this year:
7.3 325