Not sure. They have 50 prisoners. Don't know how much of them are alive. And also dont know how much of them are hostages and how much POW. Civilians are by my standard hostages (on Pierce Morgan has been said around 14) and rest are military personel, so prisoners of war. While hostages (civilians) need to be released right now without conditions, POW is different story and there can be exchange.

But you forgot other side. Israel has also lot of hostages. Hostage is every palestinian who is held in "administrative detention" - a longstanding security policy, inherited from the British, that allows the Israeli state to imprison people indefinitely without charge, and without presenting any evidence against them.