New farming methods, such as the introduction of the horse drawn plow and the heavy wheeled plow, allowed for deeper tilling of the soil, more arable tilled soil, and an increase in production. Previously, medieval farmers could anticipate a return of three seeds for every seed planted; one of which had to be saved for the following year's crop. If there were a bad year, starvation was probable. With the introduction of new farming methods, production increased from three to four seeds for every seed planted, an increase of twenty five per cent. The increase in production led to an increase in population, as more food meant better health, fewer people dying from opportunistic diseases, etc. This increase in production led to specialization, and ultimately the rise of towns and cities, which were practically non-existent during the early Middle Ages. Sadly most of the increase in production was wiped out and even reduced to a deficit in population by the Black Death which destroyed twenty five per cent of Europe's population.