Conventional electrical unit
Definition

Constant
Conventional exact value (CIPM, 1988; until 2018)
Empirical value (in SI units) (CODATA, 2014)
Exact value (SI units, 2019)
Josephson constant
KJ-90 = 483597.9 GHz/V
KJ = 483597.8525(30) GHz/V
KJ = 2 × 1.602176634×10−19 C/6.62607015×10−34 J⋅s
von Klitzing constant
RK-90 = 25812.807 Ω
RK = 25812.8074555(59) Ω
RK = 6.62607015×10−34 J⋅s/(1.602176634×10−19 C)2

Question: In 1988, what was the official value for the KJ-90 and the von Klitzing constants?
Answer: In 1988, the CIPM conventional values for the Josephson constant as exactly KJ-90 = 483597.9×10⁹ Hz/V and for the von Klitzing constant as exactly RK-90 = 25812.807 Ω.