If you had the data for each year you could just recode and augment the development variables as lagged variables for each subsequent year and move forward.
However, since you do not have the data for 1986-1989, the problem with any approach you use is the simple fact that you (I assume) have no points of verification other than the 1985 and 1990 points.
What I am getting at is that ,for example, there is no way to confirm the difference in these two temporal development patterns:
0,0,0,0,0,1
0,0,0,0,1,1
0,1,1,1,1,1
No more than you can use the data to tell the difference in a spatial area between:
A. Slow steady growth of effective radius by 10 miles each year
B. Rapid expansion of effective radius of 60 miles in 1987 followed by no more growth.
I feel for you, this is a classic example of being asked to build a path dependent analysis with no verification points on the path other than the start and end. You could build any model you want, no one can challenge its validity.
Which leads me to my next but related question, how are you going to know you are right in your analysis? You have no points of verification. For example, how are you going to possibly know if you way overestimated the probabilty in 1986 and way underestimated it in 1987? Since you are only looking at 1985 and 1990 you don't know how well you did each year without some sort of external verification.
As for the constructive part of my response, you can augment lagged variables and run correlations on them, if you had a means to verify.
Ike Eisenhauer