PHP：回显原始JSON数据而不是字符串化版本

I'm working on a webpage that sends AJAX-requests to a server to get some JSON back. In the .php-file, I simply echo the array with:

echo json_encode($array);

As far as I know, this sends back text that represents a JSON object. Are there more efficient ways (data wise) of doing this?

Boiled down, what I mean is: If I wanna send the number 53.52598895, I could do this in string format and use up a bunch of bytes, or I could send just a few bytes representing the number itself.