The F-16 is the core of Egyptian air power, as their remaining combat aircraft consists of 78 aging French Mirage F5s and Mirage 2000s, 110 Russian and Chinese MiG-21s, and 24 U.S. F-4s. The main reason Egypt has so many F-16s is because, as part of the 1977 peace deal with Israel, the U.S. has been providing several billion dollars in military and economic aid a year. The understanding is that most of this money will be used to buy American products. The F-16 seemed like a good choice, if only because Israel was very happy with them. So is the UAE, and so is Turkey and Greece. The region can be accurately described as Falcon Country.
There are actually six major models of the F-16 currently in use, and they are identified by block number (32, 40, 42, 50, 52, 60), plus the Israeli F-16I, which is a major modification of the Block 52. Another special version (the Block 60), for the UAE (United Arab Emirates) is called the F-16E. The various block mods included a large variety of new components (five engines, four sets of avionics, five generations of electronic warfare gear, five radars and many other mechanical, software, cockpit and electrical mods.) Countries like Turkey can thus add the new components and turn an older F-16 into a more powerful late model. There are also some older (Block 1, 5, 15, 20, 25, 30) aircraft out there, all with two decade old technology.
The F-16 is the most numerous post-Cold War jet fighter, with over 4,200 built, and more in production. There are 24 nations using the F-16, and 14 have ordered more, in addition to their initial order. During The Cold War, Russia built over 10,000 MiG-21s, and the U.S over 5,000 F-4s, but since then warplane production has plummeted about 90 percent. Even with the end of the Cold War in 1991, the F-16 has been popular enough to keep the production lines going. This despite the fact that the F-35 is supposed to replace the F-16. But the F-35 price keeps going up (it's headed north of $100 million per aircraft), and the F-16 continues to get the job done at half that price.