Just a decade and a half as it turns out! (though things definitely felt dizzyingly fast back then - think Google was launched just 5 years after HTML)
We are already the densest OECD city by quite a margin! (22,000 per sqkm in the inner 20 district, twice that of Manhanttan and 3 times that of Tokyo - and still 8,600 in the Petite Couronne, which includes 8 million people)