Hi @julietavuan
Ah, I found the bug, in the JS file the current year, for which the statistics should be displayed, is hard coded to 2016, s. https://github.com/pkp/pkp-lib/blob/master/plugins/generic/usageStats/js/UsageStatsFrontendHandler.js#L127-L129 
Please track this GitHub Issue for the fix: fix hard coded current year in the usage stats JS 路 Issue #2154 路 pkp/pkp-lib 路 GitHub
Best!
Bozana