Pew has just published four graphs on the pace of voter registration in four states (MD, VA, CO, FL) over time. The key finding is:

These data show the unique business cycle of an elections office, where every four years there is an explosion of voter registration activity. Officials plan for staffing and resources that are sufficient for 47 months out of the 48 month cycle and then face tremendous challenges during that one month before a presidential election registration deadline. Finding the time and labor to process these forms while also conducting the many other activities necessary to prepare for an election is a daunting task—and one that election officials will no doubt face again this fall.