1-2% for a single language at the cost of polluting an entire instruction set.
Yes this is necessitated by some of JS's big warts, but the sheer amount of javascript in existence weights heavily when considering the trade-offs. You cannot ignore HTML/JS if you're targeting UI applications - it is table stakes.
It is much more about the design of the instructions, generally RISC instructions take a small, fixed amount of time and conceptually are based on a sort of minimum unit of processing, with a weak to very weak memory model (with delay slots, pipeline data hazards, required alignment of data etc) with the compiler/programmer combining them into usable higher level operations.
CISC designs on the other hand happily encode large, arbitrarily complex operations that take unbounded amounts of time, and have very strong memory models (x86 in particular is infamous here, you can pretty much safely access memory, without any alignment, at any time, even thought often the result will be slow, it wont crash)
As an example, the PDP-8 has fewer than 30 instructions, but is still definitely a CISC architecture, some ARM variants have over 1000 instructions but are still definitely RISC.
RISC is about making building processors simpler, not about making instruction sets and programming with them necessarily simpler.
Fast forward a decade or so and all processors had cache and multi-byte memory bus so the unaligned access and compact instruction streams are no longer necessary.
But processors these days are complex multi core beasts with IEEE fpu, simd units, mmu, memory controller, cache controller, pci-e northbridge, all kinds of voltage/thermal interplay, and even iGPU. ISA is over emphasized.
From the definition given:
CISC designs on the other hand happily encode large, arbitrarily complex operations that take unbounded amounts of time, and have very strong memory models
Consumers and even manufacturers are both focused on performance as a primary metric, not the size of an instruction set.
It being RISC is secondary to that.
It was the point at, say, the original ARMv1.
I am genuinely curious, I don't know much about instruction set design.