WiFi 802.11g Non-Overlaping Channels

Hallo all. I was taking a look on the WiFi 802.11g in Wikipedia.

http://en.wikipedia.org/wiki/IEEE_802.11g-2003

Concerning the available channels they are as follow:

It is supposed that in USA there are 11 available channels (i.e. ch1-ch11) while in Europe there are 13 available channels (i.e. ch1-ch13). However, as you can see, there is also a 14th channel (fo=2,484GHz). Is this an available channel for Europe too?

These channels have a 5MHz frequency separation between them. So, in USA, we can use 3 channels the most, in order to avoid interference. I.e. we can have 3 access points -the 1st on ch1, the 2nd on ch6 & the 3rd on ch11- in the same place without interfering to each other (as the frequency separation between them is 25MHz, hence greater than the channel's BW which is 22MHz). In Europe, (Wiki claims that) we can use 4 channels the most: ch1, ch5, ch9 & ch13. Although these channels are are not exactly "non-overlaping" (there is an overlap of 2MHz at their edges) the interference is very weak, so we can use them. However, if the ch14 is an available channel then why don't we use it? So, we could use ch1, ch6, ch11 & ch14, which are clearly non-overlaping.