Find the number of web accelerators used for each Operating system.
SELECT Operating_system ,  count(*) FROM web_client_accelerator GROUP BY Operating_system
SELECT Operating_system ,  count(*) FROM web_client_accelerator GROUP BY Operating_system
[{'Operating_system': 'Android, Linux, Mac and Windows devices', 'count(*)': 1}, {'Operating_system': 'Any', 'count(*)': 1}, {'Operating_system': 'Any system with Java 1.6 VM available', 'count(*)': 1}, {'Operating_system': 'Appliance (Linux)', 'count(*)': 1}, {'Operating_system': 'Unix (Linux, *BSD, Mac OS X, others)', 'count(*)': 1}, {'Operating_system': 'Unix (Linux, *BSD, Mac OS X, others), Windows', 'count(*)': 2}, {'Operating_system': 'Windows', 'count(*)': 3}, {'Operating_system': 'Windows (2000 onwards)', 'count(*)': 1}, {'Operating_system': 'Windows, Linux, Mac OS, Symbian, WindowsMobile', 'count(*)': 1}, {'Operating_system': 'Windows, Mac', 'count(*)': 3}, {'Operating_system': 'Windows, Mac and Mobile devices', 'count(*)': 1}, {'Operating_system': 'Windows, Mac, Linux and Mobile devices', 'count(*)': 1}, {'Operating_system': 'Windows, Mac, Mobile devices', 'count(*)': 1}, {'Operating_system': 'Windows, except NT and 95', 'count(*)': 1}]