Shares of ADP (ADP) - Get Report are up 2.5 percent thus far in 2016, far better than the one percent drop in the S&P 500. The payroll provider has outperformed the index over the last two, five and ten year periods as well. Jan Siegmund, CFO of ADP, said the job expansion of the past few years provides a nice tailwind, but is not the sole basis for the company's success. 'Our clients are growing and that helps us in our revenue growth,' said Siegmund. 'Not much as one would think as only one percent of our nine percent organic revenue growth is driven by the growth of our clients, but our clients have enjoyed job growth of two percent to three percent in the last few years.' ADP pays more than 24 million people in the U.S., or one in six workers. As opposed to the U.S. Bureau of Labor Statistics (BLS) employment reports, ADP said its accuracy centers on the fact that its report is based on actual payroll data, not survey data. The BLS counts employees 'when they are paid' while ADP counts employees 'listed as active on an employer's payroll.' 'In some months we are spot-on and in other months we differ slightly, but overall the difference is nominal and shows the NER is an accurate,' said Siegmund. During the last 10 years, ADP has reported that the share of manufacturing jobs has declined from 12 percent to 10 percent. Regionally, job growth has shifted away from the Northeast and Midwest to the South and West, according to ADP. Furthermore, small companies with fewer than 50 employees that survived the recession have fared better in the labor market than companies employing 500 people or more.