[Paul2432]

This question is a hypothesis rather than trend analyis. You can do this in MS Excel, but you'll need to install the data analysis tool pack (you'll likely need the office CDs). You'll also need the complete data set (i.e. 2,5,3,6,1,3 etc). This will allow you to estimate the variance in the data, which will in turn let you estimate the likelihood that the increase in 2007 is due to chance.

Once you have this enter the 2005/2006 in one column and the 2007 data in a second column. Select "data analysis" under the "tools" menu, and then "t-test: two-sample assuming unequal variance" on the pop-up menu. In the next pop-up window enter the cell range for the 2005/2006 data in the space for variable 1 and, the cell range for the2007 data in the space for variable 2. The field "alpha" is the level of significance (lower is stricter).

For more info on hypothesis tests in general search Wikipedia on "hypothesis test".

Paul