Confusion with coverage numbers

[monikadhok]

I have the following code

var o = {};
o.tmp = function(c){
return {
a : "model"
b : function(...){
c.add(function(){
....
});
c.add(function(){
....
});
}
}
}
o.tmp();

I understand that in this execution, the function "b" can not be executed. Using istanbul, I am getting following numbers :
Statements : 55.56% ( 5/9 )
Branches : 100% ( 0/0 )
Functions : 25% ( 1/4 )
Lines : 55.56% ( 5/9 )

I don't understand how 55% of the function is executed. Most of the code is covered with the function declaration of "b". Also, what does (5/9) means? What are the 9 statements here?
Thanks in advance,
Monika