php - Finding average of same key values of an associate array -

i've have array such

//$ary, $ary contains 80 entries, i'm showing first 10 array (     [0] => array         (             [december 2012] => 58         )     [1] => array         (             [november 2012] => 84         )     [2] => array         (             [december 2012] => 83         )     [3] => array         (             [november 2012] => 72         )     [4] => array         (             [november 2012] => 47         )     [5] => array         (             [december 2012] => 93         )     [6] => array         (             [november 2012] => 79         )     [7] => array         (             [october 2012] => 70         )     [8] => array         (             [november 2012] => 75         )     [9] => array         (             [october 2012] => 59         )     [10] => array         (             [december 2012] => 67         ) ) 

i'm able total each month using:

foreach($ary $array) {        foreach($array $month=>$cent)     {          if(isset($abc[$month])) // prevent index warning         {                        $abc[$month] += $cent;            // tried using $abc[$month] = $abc[$month]/2 wrong values returned         }         else         {             $abc[$month] = $cent;         }     } } 

this resulting in

array (     [december 2012] => 2195     [november 2012] => 2159     [october 2012] => 1631 ) 

but i'm unable find way find average value each month. in case, there 31 instances of december 2012, 31 instances of november 2012 , 25 instances of october 2012. thus, need hold of these 31, 31, , 25 values can divide month number.

i'm thinking must done inside if(isset($abc[$month])) loop capture haven't been successful far. there other way average?

ps : can't hardcode month's name (october, november, december) comparison purposes. keep changing @ regular intervals.

$eachmonth = array(); foreach($ary $array) {       foreach($array $month=>$cent)   {      $eachmonth[$month][] = $cent;      if(isset($abc[$month])) // prevent index warning     {                    $abc[$month] += $cent     }     else     {         $abc[$month] = $cent;     }   } } 

then each month can calculate average:

foreach( $eachmonth $month => $values) {    echo $month.' : '.$abc[$month] / count($values);  }