The average board scores have been in the 230s, not in the 220s. Second, there were only 2 spots last year that went unmatched, but then quickly filled during the scramble. That is only 1.3% of available slots (hardly easy). The 20% drop-out rate is true, likely due to a very demanding and long training program. There has also been a shift (as has occured in other surgical specialties) to recruit research/academic types. This means a research background, publications, grants, etc are required at some places and certainly put you above the group at others.
I know several people that did not match this past year that would have been considered competitive by anyone's standards-- don't be fooled into thinking that a match into NS is easier than before.