I recently came across a rather splendid command that shows your drives and their percentage of free space. And it is -

df -hP |column -t |tee >( head -n1 > /dev/stderr ) |grep % |sort -k5nr

and in my case it shows this -

Filesystem  Size  Used  Avail  Use%  Mounted                 on
/dev/sdd1   2 ...