The Obama administration and congressional leaders have offered assurances that they don't want a government shutdown. March 4 is the deadline for them to reach an agreement.

Here's a review of some of the basic shutdown facts published in the newest Congressional Research Service report on the issue, sent to lawmakers late last week and obtained by The Federal Eye.

How long do shutdowns last?

Six shutdowns occurred between fiscal year 1977 and fiscal year 1980, ranging from eight to 17 full days, according to the report. From fiscal 1981 to 1995, nine shutdowns occurred, lasting no longer than three full days.

In fiscal 1996, the first budget impasse led to a five-day shutdown from Nov. 13-19, 1995. The second shutdown, the longest in U.S. history, stretched 21 days from Dec. 15, 1995 to Jan. 6, 1996.

How many federal workers are affected by shutdowns?

The first Clinton-era government shutdown led to the furlough of about 800,000 federal employees, according to CRS. The second shutdown furloughed about 284,000 federal employees. An unknown number of federal contractors were also affected. The federal government doesn't track the number of contractors employed by its agencies.

What kind of work can continue during a shutdown?

According to federal guidelines established in the 1980s, agencies should continue activities that: