This info comes from data leaked by Israel's Civil Administration to the advocacy group Peace Now, and reported in, among other places, the New York Times yesterday.
Some settlements are built on up to 80% privately held Palestinian land. The settlements are protected by the military and legal rulings in favour of Palestinian owners are not enforced.
Also worth noting is that other than the average 40% that belongs to Palestinians, the rest by no means belongs to Israelis. It belongs to "the state," which seems a difficult category when one is in the Occupied Territories.
The maps indicate that beyond the private land, 5.8 percent is so-called survey land, meaning of unclear ownership, and 1.3 percent private Jewish land. The rest, about 54 percent, is considered â€œstate landâ€� or has no designation, though Palestinians say that at least some of it represents agricultural land expropriated by the state.
Many of the settlements sitting on stolen Palestinian land will be annexed to Israel in any future two-state plan, and are included by the path of the infamous Wall.
Speaking of which, there are some excellent short films available on the website of the Alternative Information Center about the Wall--one about a portion of it that has been built across the yard of a school (!) and one about a Palestinian man fighting to keep his house, close to the path of the Wall, from being demolished. You can see them here (they're the top two on the page).