Reasons not to rely on the FBI's justifiable homicides

Possibly the biggest problem with justifiable homicides is that in many years states don't report the number. For example in 2010, large states such as New York, Illinois, and North Carolina didn't report their numbers at all. Indeed, 14 of the 50 states didn't report a number and the 36 that do report the number are largely not doing so accurately, since just because a state reports the numbers doesn't mean that all or even most police jurisdictions within the state are reporting the data. The laws over what is classified as a justifiable homicide have also been changing a lot over time. Even when New York did report justifiable homicides up until 2006, Hawaii has a significantly higher justifiable homicide rate than New York. The rate is about a third higher. In 2006, Illinois has a rate that is about a sixth of the rate of Hawaii. It appears that what is counted as justifiable homicides is politically determined.
2000 164
2001 222
2002 233
2003 247
2004 222
2005 196
2006 238
2007 257
2008 265
2009 266
2010 278
I don't know how the WSJ gets the claim that justifiable homicides went from 176 in 2000 to 326 in 2010. I get a 70 percent increase versus their claimed 85 percent increase, but more importantly 2000 appears to be an unusually low year -- going from 2001 to 2010 gives only a 25 percent increase.
The WSJ piece did acknowledge that the increase could be due to the changing definition of what is classified as self-defense and not an increase in shootings.
UPDATE: Rob Barry at the WSJ was nice enough to respond to my question on this last point and he notes that they included Florida in their numbers. Florida reportedly had 12 cases in 2000, 12 cases in 2001, and 48 in 2010.
UPDATE 2: There was apparently a 25% increase in justifiable homicides by law enforcement from 2000 to 2010. The data by state is still more complete for justifiable homicides by law enforcement than for civilians. For example, during the years 2003 and 2005 20 states did not have the data for civilians while 7 did not have it for law enforcement.
2000 309
2001 378
2002 341
2003 373
2004 367
2005 347
2006 376
2007 398
2008 378
2009 414
2010 387

UPDATE: A further example of the problems with reporting the numbers even in the states that report the numbers is available here.