fionas, the statistics on breastfeeding are pretty clear.
from 2010 infant feeding survey

24% exclusive breastfeeding at 5 months
60% of babies receiving some breast milk at 6 months

I'm not sure what the figure is at 12 months, but I doubt it's more than 10%

So 40% of babies are fully weaned within the first 6 months and 76% have started weaning within the first 5 months. Probably at least 90% fully weaned within the first 12 months. That's a lot of bottle feeding.