All Google Panda Updates

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; confirmed, not announced)
23. Panda Update 23 - Dec. 21, 2012 (1.3% of English queries were affected; confirmed, announced)
24. Panda Update 24 - Jan. 22, 2013 (1.2% of English queries were affected; confirmed, announced)