The term of service during the 18th century was for life. In 1793 it was reduced to 25 years. Individual conscripts were drawn from urban and rural males of Russian nationality who paid poll-tax (including serfs), upon reaching the age of twenty. Because of the large population pool available, exemptions were common with the decisions largely being left to the village elders of each community. The final stage in the selection process involved the drawing of names by lot, according to the actual requirements of the army in any given year. This might mean that virtually no recruits would be required in years where the Empire was at peace and the limited replacements required could be met through the voluntary re-enlistment of veterans nearing the end of their period of conscription. Alternatively, in the critical French invasion year of 1812 three separate levies were needed, calling up a total of fifteen males from every hundred available.