Usage of different types of wireless encryption

There are no exact numbers known on the usage of encryption on wireless networks. I've found a recent report that describes how Sophos’ director of technology strategy James Lyne collected wireless information in London (a.k.a Wardriving). Actually it was Warbiking since he apperently drove through London by bike.
He found more than 1000 hotspots in London for every mile he drove. 25% of them had poor security. 9% of the access points he found have a SSID (Service Set IDentification) that was just a default value with no random element at all (e.g. default, linksys). The most interesting thing he discovered imho is that the situation in residential areas is often reasonable. However in streets with collections of small businesses the situation was worse. The report also states that often it is easy to identify at wich company a device belongs due to poor chosen SSID like 'Company X'. Access Points found at a coffeeshop often have no wireless protection scheme at all. The report advises us to only use them with a VPN- or SSH-tunnel if possible.
After some further research I've stumbled upon a very interesting project, that I've lost out of sight for some time, WiGLE (Wireless Geographic Logging Engine). WiGLE offers a Wigle Java Client and an Android application, that can be used to record WiFi-data while wardriving. This data is collected afterwards. Their webpage offers a page with statistics of their database. In 11 years time, almost 130.000 users have reported more then 77 milion unique wireless networks. With a population of 7 bilion persons that makes that for every 100 persons, their is one WiFi-network. In their stats we can see that 19.2% of the reported networks are encrypted with WEP and 25.9% have no encryption at all. But only 6.2% is reported with it's default SSID. Of course, the situation differs from 11 years ago, but two-third of all the networks in the database were added after 2010.
Comparing with the report from Mr Lyne it seems that the situation in london regarding wireless encryption is not as bad as it probably is in less populated regions. This might be “normal” as the impact of a vulnerable network in London will probably be much higher than an open wireless network in some deserted region.