Json, node and numbers

Json, node and numbers

Strange problem:

I have the following json data:

{
"UB": {
        "Y1": {
            "A1070": "750000.00",
            "A1079": "-750000.00",
            "A1211": "206755.00",
            "A1219": "-114757.00",
            "A1220": "448934.00",
            "A1229": "-313549.00",
            "A1230": "123904.00",
            "A1239": "-24781.00"
}
}

I can easily access the data by for instance: $.each(data.UB.Y1, function(i,item){ etc

But if the json data instead is like below it is not possible to access the data with: 
$.each(data.UB.1, function(i,item){ etc

{
"UB": {
        "1": {
            "1070": "750000.00",
            "1079": "-750000.00",
            "1211": "206755.00",
            "1219": "-114757.00",
            "1220": "448934.00",
            "1229": "-313549.00",
            "1230": "123904.00",
            "1239": "-24781.00"
}
}