What was the reason behind the mid-nineteenth century, about 10 per cent of the urban population were extremely poor?

Wages increased somewhat in the early nineteenth century. But they tell us little about the welfare of the workers. The average figures hide the variations between trades and the fluctuations from year to year. For instance, when prices rose sharply during the prolonged Napoleonic War, the real value of what the workers earned fell significantly, since the same wages could now buy fewer things. Moreover, the income of workers depended not on the wage rate alone. What was also critical was the period of employment: the number of days of work determined the average daily income of the workers. At the best of times till the mid-nineteenth century, about 10 per cent of the urban population were extremely poor. In periods of economic slump, like the 1830s, the proportion of unemployed went up to anything between 35 and 75 per cent in different regions.