Percentage of companies with Wireless Local Area Networks (WLAN) -- 40 Percentage of companies planning to deploy a WLAN within 18 months -- 31 Percentage of IT professionals "very concerned" about WLAN security -- 74 Percentage of IT professionals "somewhat concerned" about WLAN security -- 20 Percentage of IT professionals who felt "very knowledgeable" about wireless security -- 24 Percentage of IT professionals who felt "somewhat knowledgeable" about wireless security -- 54 WLAN nodes shipped worldwide in 1999 - 1.4 million. WLAN nodes shipped worldwide in 2000 -- 4.9 million. Estimated WLAN node shipments in 2006 -- 55.9 million Survey sources: Allied Business Intelligence, Wireless Ethernet Compatibility Alliance, Information Security magazine.