My total year km goal for 2018 was 5000 km. I did 5431 km in total, with ~3500 km of those commuting; and that despite leaving a month out due to injury. So 6000 km for 2019 seems like a reasonable goal.
Speaking of other goals, it didn't go as well; there were plans for 4 100+ km rides and one century (161km); but in the end I did only one 100+ km ride (103 km). So these goals remain the same for this year.