Next, once a year, and in the last week of the year, the retail sales tax rate
is adjusted. The government sets the tax rate equal to a value which is the value that
would leave the debt-to-GDP ratio undisturbed in the no-shock equilibrium outlined in the
next sub-section, plus an adjustment factor that is proportional to the difference between
the actual and the target debt-to-GDP ratio b with a fiscal adjustment coefficient