Elixir calculate Pi from random points

pi.exs

defmodule Experiment do
    def pi( data \\ %{total: 0, circle: 0}, num_points) do
        %{total: total, circle: circle} = data
        case num_points do
            num_points when num_points == 0 ->
                4 * circle/total
            num_points ->
                :math.pow(:rand.uniform, 2) + :math.pow(:rand.uniform, 2)
                |> case do
                    x when x <= 1 ->
                        %{data | total: total + 1, circle: circle + 1}
                    _ ->
                        %{data | total: total + 1 }
                end
                |> pi(num_points - 1)
        end
    end
end

IO.puts Experiment.pi(100000)