Table 1: Definition of ascending and descending periods.

Period Years

(I) ascending 1964.79–1968.87, 1986.70–1989.54, 2008.95–2009.95
(II) descending 1964.53–1964.79, 1979.95–1986.70, 2000.28–2008.95
(III) ascending 1976.20–1979.95, 1996.37–2000.28
(IV) descending 1968.87–1976.20, 1989.54–1996.37