How to compare key’s value and get value in PHP array

I have an array like this

Array
(
    [10] => 0
    [30] => 2
    [90] => 5
    [365] => 10

)

Array Key have #days and value have #percentage.

Now if pass day value between 0 to 10 days then percentage will be 0, if between 11 to 30 days then percentage will be 2 if between 31 to 90 days then percentage will be 5
if 500 days then 10

My code is

    $closest = null;
    foreach ($stake as $k=>$v) {
        echo "abs($search - $closest)";
        echo "abs($k - $search)";
        if ($closest === null || abs($search - $closest) > abs($k - $search)) {
          $closest = $k;
       }
    }

but when i pass 11 it’s return 10 instead of 30