I have data for 15 years and many countries. I need to find countries that have data available with two or more years apart. See this example.

1998:1
1999:
2000:
2001:1
2002:1
2003:

With normal count function the result would be 3. However the requirement is two or more years apart. So the count should be only 2. So I want to count only the cells that have data point with 2 or three years apart. E.g. I am not interested in a serie with two data points that are in years next to each other, e.g. 1999 and 2000. On the other hand a serie with data in the years 2000 and 2003 would be interesting.

So I need a function that checks whether data is available, but at the same time checks that the at least the two following cells for the enext years, to the right of the cell with data, are blank. Is this possible to do in excel or do I need VBA? And could someone please give suggestions? I am sorry, but I was not able to present the information in a table.

I would appreciate your help.