During the first industrial revolution, workers flocked in the cities in masses because of the factories that were coming up. Individual craftsmen were kicked out of business because of manufacturing, and this allowed consumers to access cheaper products much faster. Although some workers were replaced, new jobs were created and as time passed by, employment levels rose up to all-time highs. It is with certainty that technology will eliminate very many jobs, from a few million to more than a billion. According to Andrew Charlton, "This huge variance is due to the fact that we are not yet sure about the number of jobs that robots will take over in the next couple of years; we are not sure where technology will be headed."