mean difficulty increment over last 6 increments.... 21.5890372%
mean difficulty increment over 6 increments previous to that... 28.2274193%
mean difficulty increment over last 12 increments... 24.8641200%
for what it's worth.
Difficulty History from: --
http://bitcoinwisdom.com/bitcoin/difficultyDate Difficulty Change Hash Rate
Feb 28 2014 3,815,723,799 21.92% 27,314,015 GH/s
Feb 17 2014 3,129,573,175 19.39% 22,402,357 GH/s
Feb 05 2014 2,621,404,453 19.49% 18,764,744 GH/s
Jan 24 2014 2,193,847,870 22.59% 15,704,175 GH/s
Jan 13 2014 1,789,546,951 26.16% 12,810,076 GH/s
Jan 02 2014 1,418,481,395 20.12% 10,153,885 GH/s
Dec 21 2013 1,180,923,195 30.01% 8,453,378 GH/s
Dec 10 2013 908,350,862 28.41% 6,502,229 GH/s
Nov 29 2013 707,408,283 16.07% 5,063,826 GH/s
Nov 17 2013 609,482,680 19.29% 4,362,847 GH/s
Nov 05 2013 510,929,738 30.70% 3,657,378 GH/s
Oct 26 2013 390,928,788 46.02% 2,798,377 GH/s
Oct 16 2013 267,731,249 41.45% 1,916,495 GH/s
Oct 06 2013 189,281,249 27.19% 1,354,928 GH/s
Sep 25 2013 148,819,200 32.13% 1,065,289 GH/s
Sep 14 2013 112,628,549 29.56% 806,227 GH/s
Sep 04 2013 86,933,018 32.22% 622,291 GH/s
Aug 24 2013 65,750,060 29.40% 470,657 GH/s
Aug 13 2013 50,810,339 35.88% 363,715 GH/s
Aug 03 2013 37,392,766 19.63% 267,668 GH/s
Jul 22 2013 31,256,961 19.47% 223,746 GH/s
Jul 11 2013 26,162,876 22.63% 187,281 GH/s
Jun 29 2013 21,335,329 10.32% 152,724 GH/s
Jun 16 2013 19,339,258 23.92% 138,436 GH/s
Jun 05 2013 15,605,633 28.41% 111,709 GH/s
May 25 2013 12,153,412 8.64% 86,998 GH/s
May 12 2013 11,187,257 11.03% 80,082 GH/s
Apr 30 2013 10,076,293 12.28% 72,129 GH/s
Apr 17 2013 8,974,296 16.96% 64,241 GH/s
Apr 05 2013 7,673,000 14.59% 54,925 GH/s
Mar 24 2013 6,695,826 38.13% 47,931 GH/s
Mar 14 2013 4,847,647 10.98% 34,701 GH/s
Mar 01 2013 4,367,876 19.63% 31,266 GH/s
Feb 18 2013 3,651,012 11.47% 26,135 GH/s
Feb 05 2013 3,275,465 10.33% 23,447 GH/s
Jan 23 2013 2,968,775 -8.64% 21,251 GH/s
Jan 08 2013 3,249,550 9.06% 23,261 GH/s
Dec 26 2012 2,979,637 -11.59% 21,329 GH/s
Dec 10 2012 3,370,182 -2.00% 24,125 GH/s
Nov 26 2012 3,438,909 2.08% 24,617 GH/s
Nov 12 2012 3,368,767 1.95% 24,115 GH/s
Oct 30 2012 3,304,356 7.55% 23,654 GH/s
Oct 16 2012 3,072,322 0.58% 21,993 GH/s
Oct 03 2012 3,054,628 6.65% 21,866 GH/s
Sep 19 2012 2,864,141 6.31% 20,502 GH/s
Sep 06 2012 2,694,048 10.38% 19,285 GH/s
Aug 25 2012 2,440,643 11.40% 17,471 GH/s
Aug 12 2012 2,190,866 7.57% 15,683 GH/s
Jul 30 2012 2,036,671 9.12% 14,579 GH/s
and of course hardware mfgs dole it out like diamond merchants..