The modern KKK is not one organization; rather it is composed of small independent chapters across the United States. According to a 1999 ADL report, the KKK's estimated size then was "No more than a few thousand, organized into slightly more than 100 units." In 2017, the Southern Poverty Law Center (SPLC), which monitors extremist groups, estimated that there were "at least 29 separate, rival Klan groups currently active in the United States, and they compete with one another for members, dues, news media attention and the title of being the true heir to the Ku Klux Klan." The formation of independent chapters has made KKK groups more difficult to infiltrate, and researchers find it hard to estimate their numbers. Analysts believe that about two-thirds of KKK members are concentrated in the Southern United States, with another third situated primarily in the lower Midwest.