ProjectHoneyPot
www.ProjectHoneyPot.org also list India as the top offender recently, however the ranking of the rest is quite different.
Top Spam Server Countries (last 30 days)
#1 [India] India (27.3%)
#2 [Saudi Arabia] Saudi Arabia (7.1%)
#3 [Vietnam] Vietnam (6.9%)
#4 [Peru] Peru (5.8%)
#5 [Brazil] Brazil (4.6%)
#6 [China] China (4.2%)
#7 [Kazakhstan] Kazakhstan (4.2%)
#8 [Turkey] Turkey (3.0%)
#9 [South Korea] South Korea (2.5%)
#10 [United States] United States (2.3%)
#11 [Romania] Romania (2.1%)
#12 [Russia] Russia (2.0%)
#13 [Pakistan] Pakistan (2.0%)
#14 [Great Britain] Great Britain (1.7%)
#15 [Colombia] Colombia (1.5%)
#16 [Argentina] Argentina (1.5%)
#17 [Mexico] Mexico (1.4%)
#18 [Italy] Italy (1.3%)
#19 [Poland] Poland (1.3%)
#20 [Germany] Germany (1.3%)
#21 [Taiwan] Taiwan (1.1%)
#22 [Iran] Iran (1.1%)
#23 [Spain] Spain (0.9%)
#24 [Chile] Chile (0.9%)
#25 [Morocco] Morocco (0.9%)