Table:
text: Miguel Malvar-class corvette
Ships in Class
Ships in Class
Bow_number Ship_name Launched Commissioned Service
PS-18 BRP Datu Tupas 14 November 1943 November 1975 Philippine Navy Patrol Force
PS-19 BRP Miguel Malvar 1 March 1944 November 1975 Philippine Navy Patrol Force
PS-20 BRP Magat Salamat 19 March 1944 November 1975 Philippine Navy Patrol Force
PS-22 BRP Sultan Kudarat 18 May 1943 November 1975 Philippine Navy Patrol Force
PS-23 BRP Datu Marikudo 18 March 1944 5 April 1976 Philippine Navy Patrol Force
PS-28 BRP Cebu 10 November 1943 July 1948 Philippine Navy Patrol Force
PS-29 BRP Negros Occidental 24 February 1944 July 1948 Philippine Navy Patrol Force

Question: When was the ship of the Miguel Malvar class corvette commissioned in November 1975 with a bow number of PS-18?