There were no documented tornadoes in Jacksonville in 2010.
There were 105 tornadoes that hit Iowa in 2008.
In the 30 year period of 1981-2010 Iowa averaged about 1 tornado related death per year. However, it varies widely from year to year. Some years saw not deaths from tornadoes in that state, while in 2008 13 people died from tornadoes in Iowa, 9 of them from a single tornado.
Iowa averages 35 tornadoes every year.
35 is an average number of tornadoes per Year in Iowa.
There were 48 recorded tornadoes in Illinois in 2010.
The U.S. had 1282 tornadoes in 2010.
There were 8 tornadoes in California in 2010.
Seeing as this question was asked in 2010, the United States experienced 1282 tornadoes in 2010. In the past year of 2011 there were at least 1660 tornadoes in the U.S. Statistics outside the U.S. are not available.
Essentially 100% Iowa gets at least a few tornadoes every year.
From 1990 to 2010 (for which accurate tornado records are available) Minnesota has averaged 44 tornadoes per year.
Michigan averages around 13 tornadoes each year.
Not since official record keeping began in 1950. Prior to that it would be difficult to determine if there was a year with out tornadoes (though it is unlikely) as weak tornadoes were simply ignored.