Let's say that at t = 0, it is the year 1995, so we know that:

So, at t = 4, we get:

We know that:

Where b is the y-intercept, which is , that gives us:

Now, all we need to to is set it equal to to solve for a:

So, we now have an equation:

And, now we find t = 10:

And there you go.