"+" and "-" output of the Jobs command

"+" and "-" output of the Jobs command

What does the "+" and "-" signs mean in the following output of the jobs
command.
-bash-4.1$ jobs
[1]- Running awk '{print $1,$2,$3,$4}' final_ped.ped >
only_ped &
[2]+ Running awk '{if($6==1 || $6==2) print $1,$2}'
final_ped.ped > comp_list &