1980s
Kardashev
Value: 0.7
Min: 0.67
Max: 0.73
Confidence: CalculatedGuess
References:
Accourding to the source power consumption is 4 times the biomass baseline: 1200 W.
The source also tells 28564 TWh in 1950, which amounts to 2800 W per person.
Taking the latter.
Population
Value: 4e9
Min: 3.5e9
Max: 4.5e9
Confidence: Canon
References:
Quick Wikipedia research. Error bars guestimated.
Nuclear power, globalization, mass market industrial products like cars, TVs, washing machines.