Does anyone know how these are generated? Could anyone explain what this paragraph means from their FAQ: "Since 1992 at least 24 companies have set out to sol

Does anyone know how these are generated? Could anyone explain what this paragraph means from their FAQ: "Since 1992 at least 24 companies have set out to solve the random integer problem. Most fail for obvious reasons. It is rumored that a few of our competitors may have a 1-5 algo that works approximately 40% of the time. Our 1-100 algo is rock solid. In short, there is a consumer need for a random integer but the problem isn't easy. Even Google is rumored to be 2 years away from a reliable 1-50 algo." I'm probably being stupid but I don't understand what 'works approximately 40% of the time' means in this respect. Also this is cool : https://www.fourmilab.ch/hotbits/secure_generate.html https://www.fourmilab.ch/hotbits/secure_generate.html