POLL: Erratic Gem Drop Rate or Simply Bad Luck with Hextech Crafting?

I must have terrible luck.

Since Dec. 15th I've opened a total of 147 Hextech Chests (maybe a few more if you count Poro King Chests) and yet I have garnered only 3 Gems. That equates to an overall drop rate of 2%.

I understand Gems are a random drop with a 4% chance, but it seems to me that 147 chests is a fairly decent sample size. Yet I only have half the Gems I should have, and those three gems all dropped in the first ~75 chests.

I find it very interesting that the Gems dropped at the assigned rate for those first ~75 chests and then suddenly stopped dropping. Of course I've also heard of people getting 10 gems in less than 100 chests, which if true is more than double the standard drop rate.

I spent about $250 on RP to purchase those 147 chests and I have roughly $400 worth of champs/skins/icons to show for it along with a remainder of about 3k RP, so its not a total loss. However, current drop rate considered I'm about to give up on getting the Hextech Annie skin because at this rate it would cost me close to $1000 to procure the required 10 gems.

Seems to me that the drop rate (which I understand is random) is highly erratic and maybe could be either increased or made more reliable somehow. Just my 2 cents. What are your thoughts?