At first sight I thought the max. was 1.00 like 100% but obviously I was wrong. Anyone knows more?
Should have done a search before asking ;- )
Adoption for multicore and percentage would be really nice....
Luci statistics has also stats for CPU utilization per core.
Regarding system load stats, feel free to suggest changes to upstream Linux kernel, as the load number has been calculated this way in all Unix variants since ages.
Despite the intuitive and charming result of my approach I assume kernel team has other tasks with a higher priority or if it's done like ages as you said the would perhaps react like the catholic church and I will ran against a massive wall of tradition ;- ) ...or good arguments against it.