ActionScript 1/2 :: Cannot Read RadioButton Data In Function

There's a RadioButtons group (=Group3) and event listener applied on it. The value of _root.choices3.a3.data is "a". The code is following:

trace("DATA BEFORE" + _root.choices3.a3.data);
var rbListener3 = newObject();
rbListener3.click = function() {
trace("I am inside.")
trace("DATA INSIDE" + _root.choices3.a3.data);
}
_root.choices3.Group3.addEventListener("click",
rbListener3);

If I compile it, the output is:
DATA BEFORE
I am inside.
DATA INSIDE
Why can't I read the value of _root.choices3.a3.data inside the function?