How out of date are googles photomaps?

I was curious as to how out of date googles photomaps are in the US and Europe. So I made these list of the top 10 cities by population and zoomed into the CBDs on google earth to determine the aerial capture dates.

US are on average ~14.1 months out of date, and EU are on average ~28.5 months out of date.

http://en.wikipedia.org/wiki/List_of_United_States_cities_by_population
http://en.wikipedia.org/wiki/Largest_cities_of_the_European_Union_by_population_within_city_limits

Top 10 US

	Column 1	Column 2	Column 3	Column 4
0	City	Google image	Days	Months
1	New York	3/06/2011	1,156	38.0
2	LA	17/04/2013	472	15.5
3	Chicago	3/04/2013	486	16.0
4	Houston	9/04/2014	115	3.8
5	Philidelphia	8/10/2011	1,029	33.8
6	Phoenix	8/03/2014	147	4.8
7	San Antonio	8/02/2014	175	5.8
8	San Diego	14/11/2013	261	8.6
9	Dallas	19/10/2013	287	9.4
10	San Jose	24/02/2014	159	5.2
11	average	429	14.1

Top 10 EU

	Column 1	Column 2	Column 3	Column 4
0	City	Google image	Days	Months
1	London	19/07/2013	379	12.5
2	Berlin	27/07/2012	736	24.2
3	Madrid	27/08/2011	1,071	35.2
4	Rome	17/06/2013	411	13.5
5	Paris	1/08/2008	2,192	72.1
6	Bucharest	3/08/2012	729	24.0
7	Vienna	17/08/2011	1,081	35.5
8	Hamburg	21/07/2013	377	12.4
9	Budapest	16/04/2013	473	15.6
10	Warsaw	1/04/2011	1,219	40.1
11	average	867	28.5