Displaying data object in wrong category

Question

I have the following implementation:

http://jsfiddle.net/c1dfuj1s/3/

I have two catgeories : 1970 and 1975.

My question is that even though I am adding a data to 1975, but it adds to 1970.

{
   "series": "item6",
   "category": "1975",
   "value": 105
 },

Answer 1

Not sure exactly why this happens, but you can solve it by adding a zero value item 6 to 1970:

 {
    "series": "item6",
    "category": "1970",
    "value": 0
},  
    {
    "series": "item6",
    "category": "1975",
    "value": 105
},

Updated FIDDLE