multi dimensional array question

hello everybody here is my array(s) $us_census = array('NY' => array('New York' => 8008278), 'CA' => array('Los Angeles' => 3694820, 'San Diego' => 1223400), 'IL' => array('Chicago' => 2896016), 'TX' => array('Houston' => 1953631, 'Dallas' => 1188580, 'San Antonio' => 1144646), 'PA' => array('Philadelphia' => 1517550), 'AZ' => array('Phoenix' => 1321045), 'MI' => array('Detroit' => 951270)); print "<table><tr><th>State</th><th>City</th><th>Population</th><th>Total</th></tr>"; // $state is the key and $states is the value foreach ($us_census as $state => $cities) { // $state is the key and $habitant is the value foreach ($cities as $city => $habitants){ print "<tr><td>$state</td><td>$city</td><td>$habitants</td><td></td></tr>"; } } Now i also want to be able to count the total population per state, i am stucked...