loop do
  n, w = gets.split.map(&:to_i)
  break if n == 0
  v = n.times.map{ gets.to_i }
  max = v.max / w
  count = [0.0] * (max + 1)
  v.each{ |i| count[i / w] += 1 }
  puts count.map{ |c| c / count.max }
      .map.with_index{ |c, i| c * (max - i) / max }.reduce(:+) + 0.01
end