For questions about the reputation graph listed in your profile summary, or the reputation graph available on your Stack Exchange network profile.
The reputation graphs are available to give visual representations of reputation gain/loss over time. A per-site reputation graph is available in your profile on the summary tab of each separate Stack Exchange site. This bar graph shows your reputation gain/loss for each day. A line graph of all sites you participate with more than 200 reputation is available on your network profile.
For questions about your reputation history (or reputation tab), please use the reputation-history tag.