looping over an array of objects with not unique keys.?

Question

i have the following json structure:

{
    "zip":
    [
        {
            "60656": [{
               "requestcount": "1",
                "mkId": 20005,
                "mdId": 22378,
                "vehicle_make": "BMW",
                "vehicle_model": "X5",
                "stkTypId": 28881
            },
            {
                "requestcount": "1",
                "mkId": 20005,
                "mdId": 22378,
                "vehicle_make": "BMW",
                "vehicle_model": "X5",
                "stkTypId": 28881
            },
            {
               "requestcount": "1",
                "mkId": 20005,
                "mdId": 22378,
                "vehicle_make": "BMW",
                "vehicle_model": "X5",
                "stkTypId": 28881
            }]
          },
          {
            "77054": [{
               "requestcount": "1",
                "mkId": 20005,
                "mdId": 22378,
                "vehicle_make": "BMW",
                "vehicle_model": "X5",
                "stkTypId": 28881
            }]
        }
    ]
}  _.forEach(json.zip, function(key, value) {
        console.log("********************************************************************************************************")
        console.log(key);
        for (var i in key) {
            console.log("&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&");
            console.log(i);
            console.log("&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&");
        }

    });  

What is the best to loop over this entire structure? I am trying to gain access to the stkTypId in each of the unique Zipcode keys.

I have tried this in a few ways so far but unsuccessful. Also i tried formatting this json code, but for some reason stackoverflow would not let me post the question.