By the 1870s, the practice had spread to many countries, though limited to larger cities.
By the turn of the century the practice had spread to most Western democracies.
Since then the practice has spread to local affluent men.
Even though companies won't be required to follow suit, perhaps a similar practice will spread.
These practices had spread to many families outside the ruling class.
How far the practice may spread is a matter of speculation.
The union said the practice could spread to other shows, depriving its members of work.
By the second half of the century, the practice was spreading.
The practice even spread to some who could barely afford it.
Like all experiments, if it were to be successful, the practice would spread.