Another way:

sub sort_curr0($$) { $hash{$_[0]}{current}[0] <=> $hash{$_[1]}{current
+}[0] }

my @sorted_keys = sort sort_curr0 keys %hash;

print "$_ => $hash{$_}{current}[0]\n" for @sorted_keys;
[download]

BTW, use warnings is probably more important than use strict. But go ahead and do both.