ASDF scrambles were close to 230 in both fiscal years 2005 and 2006 before jumping to 307 in fiscal year 2007. Thus, the latest figure is a return to average/normal.
It might be interesting to note that General Toshio Tamogami was head of the ASDF from March 2007-November 2008. The General is best remembered for his strong views on history and warnings about the Chinese threat. He was fired on October 31, 2008 for writing a contest essay asserting that the US was the aggressor in WWII and Japan the victim.
General Tamogami was in command of the ASDF through fiscal year 2007 (April 2007-March 2008), which saw the greatest number of Japanese scrambles. He was, however, only in charge through half of fiscal year 2008 (April 2008-March 2009).
As I only know what I read, in English, I am not aware if charts and graphs were presented at the Thursday briefing. It would be interesting to see the number of foreign plane incursions graphed by month.
Many factors can contribute to an increase or decrease in foreign probes of Japan’s air space, with weather being one of them. Yet, I am curious if the number of scrambles against Chinese and Russian planes began to drop beginning in November 2008. But what do I know, I'm just a girl.