You don't listen and you don't learn. 

All we know for sure is that the number of homeless in Eugene is probably a good bit larger than the number counted on a given night in January, mostly by volunteers. Because of the camping ban and other reasons, homeless people hide. So you can estimate that the number homeless at any given time is some multiple of the number counted. A few thousand is probably a decent guess, but it is an educated guess.

Couch surfers cannot be counted, and they are homeless. It's an unstable situation.

The statistics kept by local nonprofits who provide services or shelter to the homeless provide a total of how many individuals they served in a year. This is much more reliable. Last year "12,998 individuals who sought services from local human services programs were homeless at some point during the year". Most people are only homeless temporarily, so there is a lot of turnover.