I have met Kashmiris and although I would not entirely agree with the survey as far as I saw it but the voice for independence is pretty great.
Perhaps, Pakistanis are mostly surprised at the high percentage of demand for indepdence in AJK. Well 44% is way too, but I'd say it isn't entirely false. AJK already enjoys a lot of autonomy and they exert pressure on the Federal Government whenever they want, demand subsidized electricity (Mangla hamara hai) and pay way too little taxes compared to the rest of Pakistan.
We're indoctrinated that Kashmir is ours, rightfully ours and "Kashmir ban ke rahay ga Pakistan". Hence nobody even knows that a UN administered plebiscite if held (ever), then it will have to be held in AJK and GB as well, for India has claim over them (more over AJK and less over GB) as much as we have a claim over occupied Kashmir. Hence, it's not surprising that they too view Independence an option. Also keep in mind that GB was running effectively thanks to extensive works by the Agha Khan Foundation. Had it not been for them, rebellious voices would have risen in GB as well.
As for the occupied Kashmir, I met a whole bunch of Uni of Srinagar MBA students on a trip to Delhi and we used to spend time with the whole bunch at night after the whole tourist things. One of them was a diehard freedom fighter having lost a brother in the movement but all of the rest were all for Independence or had no opinion about the whole issue. Nobody among them 30 or so I might wanted to be with Pakistan, 1 wanted to be with India and the rest 28 wanted to go Independent.
But as far as I see it, Independence for them is unrealizable.