December jobs numbers reported Tuesday show that job creation slowed in Iowa during the last half of 2013, according to a report from the Iowa Policy Project, a nonpartisan liberal think tank in Iowa City. Iowa was adding an average of  2,300 jobs a month in the first half of 2013, but that pace slowed in the second half of the year, creating a yearly average of 1,100 new jobs a month. The state had been adding 1,700 jobs a month for the previous two years.  According to project researcher Heather Gibney, the state needs to add a total of 63,200 jobs to catch up with population growth.