The amount of territory they cover is going to vary greatly by region and congregation. Some still cover their territory every few weeks and some do it once or twice a year.
Regardless there is absolutely no question at all that door to door is THE WORST method in the year 2015. Anyone under the age 0f 65 doesn't give a fuck about what two people knocking at the door have to say. Magazines and books just end up in the trash.