Question: Cyril Havermans is a Dutch musician, best known for being in the progressive rock band, Focus,  a Dutch rock band formed in Amsterdam in which year, by keyboardist, vocalist, and flutist Thijs van Leer?

Context paragraphs:
Cyril (album): Cyril is the first solo album by Dutch singer-songwriter Cyril Havermans.  It was recorded in 1973 after Havermans left Dutch progressive rock band Focus.  The parting was amicable and came about partly as a result of Havermans' desire to include more vocal content (Focus are primarily an instrumental band).  His erstwhile band-mates contribute much instrumentation to the album.

Cyril Havermans: Cyril Havermans is a Dutch musician, best known for being in the progressive rock band, Focus.

Focus 9 / New Skin: Focus 9 / New Skin is the ninth studio album by the Dutch progressive rock band Focus, released in 2006.  This time Pierre van der Linden (drummer of the classic 1970s Focus lineup) joins Thijs van Leer with Bobby Jacobs remaining on bass and Niels van der Steenhoven replacing guitarist Jan Dumée.

Focus Plays Focus: Focus Plays Focus (better known as its international title In and Out of Focus) is the first studio album from the Dutch rock band Focus, released in 1970 on Imperial Records.  It was the band's only album recorded with the original line-up of Thijs van Leer, Jan Akkerman, Martin Dresden and Hans Cleuver.

Golden Oldies (album): Golden Oldies is the eleventh studio album by the Dutch progressive rock band Focus, released on 14 April 2014.  The album consists of newly recorded versions of the most popular songs from the band's back-catalogue, including "Hocus Pocus" and "Sylvia", performed by the current line-up as of 2012: Thijs van Leer, Pierre van der Linden, Menno Gootjes, and Bobby Jacobs.

Focus (Jan Akkerman &amp; Thijs van Leer album): Focus is a studio album by Dutch musicians Jan Akkerman and Thijs van Leer, released in 1985 on Vertigo Records.  The album's name is due to the only original members on the record being guitarist Jan Akkerman and flautist/keyboardist Thijs van Leer.

Focus (band): Focus are a Dutch rock band formed in Amsterdam in 1969 by keyboardist, vocalist, and flautist Thijs van Leer.  The band have undergone numerous formations in its history; since December 2016 it has comprised van Leer, drummer Pierre van der Linden, guitarist Menno Gootjes, and bassist Udo Pannekeet.  Other important members include guitarist Jan Akkerman and bassist Bert Ruiter.  They have sold one million RIAA-certified albums in the United States.

Focus II: Focus II (better known as its international title Moving Waves) is the second studio album from the Dutch rock band Focus, released in October 1971 on Imperial Records.  Following the departure of Martin Dresden and Hans Cleuver in 1970, the band recruited Cyril Havermans on bass and Pierre van der Linden on drums and proceeded to work on new material.  The album includes "Hocus Pocus", the group's most successful single, and "Eruption", a 22-minute track based on the opera "Euridice" by Jacopo Peri.

Hocus Pocus (song): "Hocus Pocus" is a 1971 song from "Focus II" (a.k.a. "Moving Waves"), the second album by Dutch rock group Focus.  It was written by guitarist Jan Akkerman and flautist-keyboardist Thijs van Leer.

Thijs van Leer: Thijs van Leer (pronounced: /tɛis vɑn lɪ:r/ ; born 31 March 1948) is a Dutch musician, singer, songwriter, composer and producer, best known as the founding member of the rock band Focus as its primary vocalist, keyboardist, and flautist.  Born and raised in Amsterdam among a musical family, van Leer took up the piano and flute as a child and pursued them at university and music academies.

Supporting paragraphs: Cyril Havermans Focus (band)
Answer: 1969