27.09.2008 - time gap of 61 days
27.07.2008 - time gap of 225 days
12.01.2008 - time gap of 76 days

27.10.2007 - time gap of 180 days
30.04.2007 - time gap of 97 days
25.01.2007 - time gap of 15 days
10.01.2007 - time gap of 104 days

28.09.2006 - time gap of 77 days
13.07.2006 - time gap of 100 days
04.04.2006 - time gap of 45 days
18.02.2006 - time gap of 122 days

19.10.2005 - time gap of 97 days
14.07.2005 - time gap of 83 days
22.04.2005 - time gap of 111 days
01.01.2005 - START

Next Pagerank upgrade? Approx. December, 2008.