Google Panda Algorithms Updates from February 2011 to November 2012

1. Panda Update 1, Feb. 24, 2011 (11.8% of queries; announced; English in US only)
2. Panda Update 2, April 11, 2011 (2% of queries; announced; rolled out in English internationally)
3. Panda Update 3, May 10, 2011 (no change given; confirmed, not announced)
4. Panda Update 4, June 16, 2011 (no change given; confirmed, not announced)
5. Panda Update 5, July 23, 2011 (no change given; confirmed, not announced)
6. Panda Update 6, Aug. 12, 2011 (6-9% of queries in many non-English languages; announced)
7. Panda Update 7, Sept. 28, 2011 (no change given; confirmed, not announced)
8. Panda Update 8, Oct. 19, 2011 (about 2% of queries; belatedly confirmed)
9. Panda Update 9, Nov. 18, 2011: (less than 1% of queries; announced)
10. Panda Update 10, Jan. 18, 2012 (no change given; confirmed, not announced)
11. Panda Update 11, Feb. 27, 2012 (no change given; announced)
12. Panda Update 12, March 23, 2012 (about 1.6% of queries impacted; announced)
13. Panda Update 13, April 19, 2012 (no change given; belatedly revealed)
14. Panda Update 14, April 27, 2012: (no change given; confirmed; first update within days of another)
15. Panda Update 15, June 9, 2012: (1% of queries; belatedly announced)
16. Panda Update 16, June 25, 2012: (about 1% of queries; announced)
17. Panda Update 17, July 24, 2012:(about 1% of queries; announced)
18. Panda Update 18, Aug. 20, 2012: (about 1% of queries; belatedly announced)
19. Panda Update 19, Sept. 18, 2012: (less than 0.7% of queries; announced)
20. Panda Update 20 , Sep. 27, 2012 (2.4% English queries, impacted, belatedly announced
21. Panda Update 21, Nov. 5, 2012 (1.1% of English-language queries in US; 0.4% worldwide; confirmed, not announced)
22. Panda Update 22, Nov. 21, 2012 (0.8% of English queries were affected; 0.4% worldwide; confirmed, not announced)