The defining Tikkun at Samech is to be in the next Machzor, just before Chochma reaches 72. However, in a manner similar to the Tikkun of Aleph Sofit, the Tikkun of Samech "grows" at two instances before 72. The Zohar refers to them as 60, and as 66 and a fraction (See, for instance, here).
The Tikkun of 60 occurred in year 5727, in year Samech of the Machzor. It was the six-day war. This was when Malchut reached 499, and also 500, as Yovel first strenghtened Malchut, which lifted Chochma to 59. Hence, ך" ס" ה"ם תצט"א. Tartei Mashma.
The Tikkun of 66 and a fraction will be in year Samech of the current Machzor.
נד