Here's Earth Policy Institute's car and bike production data as a proportion of world population. All this does is take some of the upward slope out of the curves. Car production as a proportion of population has been basically flat since 1974, while bike production actually took off about that time. Ah, 1988. In absolute terms (see EPI's graph here
http://www.earthpolicy.org/Indicators/Bike/BikeAuto.gif), there was a bike boom that started in 1969 and continued almost unabated until 1988, with no bust. In population-relative terms, the dip from 1973 to 1975 is a bustlet (bike production loses a quarter of its value), but then proceeds to double from 1975 to 1988, and now looks like it's stabilizing.
Either way, there was a world-wide "bike boom" from 1969 to 1988, with more or less no major bust, in which bike production quadrupled in absolute terms and trebled in population-relative terms.
Hmm. 1988. Isn't that about the year that it started getting hard to buy anything new at a reasonable price except a hideous, cheapo mountain bike with a sloping top tube?
Eric