Need to determine the fraction of a matrix of ones and zeroes that are zeroes

I need to determine the fraction of a matrix of ones and zeroes that are zeroes.

My code is:

function y = zero_stat(Y)
K=mean(Y');
[x,y] = size(Y');
r = mean(Y',y);
s = sum(r);
y=(1-s)/y)*100;
end

IF 40% of the matrix is comprised of zeroes, the function is to return 40.

Answer 1

[Walter Roberson]

mean(Y(:)) * 100

[Jan]

Because the zeros should be counted:

(1 - mean(Y(:))) * 100

Answer 2

[Steven Lord]

Get the number of nonzeros using nnz and the total number of elements using numel.