Well, if you want to get technical, let's do that.
Spain was never 100% Muslim-controlled then. In 711, the moors swept over the peninsula easily defeating the fragmented Visigothic ruler Leovigild. In the space of two years, they were crossing the Pyrenees ready to move on France until the Franks stopped them, [allegedly by serving them spoiled hotdogs at the "Franks vs. Moors Sporting Challenge Games of 778"].
The only pockets of resistance/unconquered territory were parts of present-day Euskadi and the Picos de Europa region of present-day Asturias (near Covadonga). History, of course, reveals that at least one of these pockets became Christian Spain, and the birthplace of the "Reconquest".
The infighting and outfighting between Christian rulers, their brothers, cousins and then the Moors, continued for centuries. Those who think the "reconquest" of Spain was a Christian vs. Muslim holy war are out of touch with the facts. Christians fought amongst themselves as much as they fought the Muslims, and many times they struck alliances with the Moors in order to further their own political motives.
There were a few key turning-point battles like Navas de Tolosa in 1212, but for the most part, the Caliphate of Cordoba and subsequently Granada were the major Moorish-influence mainstays. These comprised maybe a third of the peninsula at their apogee and didn't last the entire "800" years.
The startling statistic here to me is the fact that the Christian "renconquerers" didn't realize what had allowed the Moors to conquer the peninsula in a matter of a couple of years: Unity vs. a system in civil war. Had they remained unified and fixed on a common goal, they might have removed the Moorish "threat" in a much more timely fashion, much more inexpensively, and with less loss of life.
Okay, you can all wake up now. The lesson is over.