How do I replace this for-loop?

[Robert Macy]

What's the best way to replace this for-loop?

Given an array, n, of datapoints, such that:

>> size(n)
rows = 27000
columns = 2

where n(:,1) are all the integer x values, and
n(:,2) are all the integer y values, 
both integer values are in the range of 1 to 101

I slowly did it this way:

output=zeros(101,101);
for i=1:27000
  output( n(i,1),n(i,2) ) = output( n(i,1),n(i,2) ) + 1;
endfor

as you all know this is fairly slow.
What's a simple way to replace this for-loop?

Robert