why my output in json data contain extra curly braces : The main problem of this  code is that it provides extra curly braces ..

    <?php 	
    header('Content-Type: json');
	include('config.php');
	
		for($i=1990;$i<=2016;$i++){
			$sum=0;
			$data1=array();
			$result=mysql_query("select * from crimedetails  where crime_year=$i");
            while($row=mysql_fetch_array($result))
              {
				$sum+=$row['crime_mudered'];
				$data['crime_mudered']=$sum;
				$data['crime_year']=$row['crime_year'];
				}
			  $data3[]=$data;
		}			
		array_push($data1,$data3);
		print json_encode($data1);
?>

[enter image description here][1]


  [1]: http://i.stack.imgur.com/fbdBs.png