Is there any way to check the "time" (eg activity periods you posted it) you currently have? (Other than getting a bunch of posts till your activity stops climbing)
There was a website that did that, but it went down a long time ago. What you can do is take a look at the table VB1001 posted above and see in which periods you posted at least once. Since you only have 18 posts, it's something easy to do. But for cases like mine (4000+ posts), it's pretty impossible without a script/tool that does that automatically.