>perl -E"$h{rand()}++ for 1..1e6; printf qq[prob: %.3f%%\n], (keys(%h)/1e4)" prob: 3.277% >perl -E"$h{rand()}++ for 1..1e6; printf qq[prob: %.3f%%\n], (keys(%h)/1e4)" prob: 3.277% >perl -E"$h{rand()}++ for 1..1e6; printf qq[prob: %.3f%%\n], (keys(%h)/1e4)" prob: 3.277% >perl -E"$h{rand()}++ for 1..1e6; printf qq[prob: %.3f%%\n], (keys(%h)/1e4)" prob: 3.277%