Business Insider Here they are: the most important charts in the world.

A lot has changed since the last time we published this collection back in July.

The economic situation in Europe has deteriorated, the unemployment rate in the US has fallen below 6%, and the Fed looks poised to conclude its quantitative easing program this week.

Volatility has returned to markets, with the S&P 500 recently declining more than 9% before sharply rebounding, while the bond market had one of its most volatile days in history as the US 10-year yield fell 37 basis points in just a few hours.

And in the background of all of this is the declining price of oil, which on Monday fell below $80 a barrel for the first time in over two years, and a Russian economy that is looking at a dramatically depreciating ruble.

We asked our favorite economists, analysts, bloggers, and hedge fund managers for the chart they're watching right now. What they responded with was a collection of charts reflecting the increasing market fears about deflation, the economic malaise in the eurozone, and the growing suspicion that maybe the Fed's QE program will be reinstated faster than many people currently expect.

And despite the uncertainty, many of our experts offered reasons why we should be optimistic.

So without any further ado, here is what some of the sharpest folks on Wall Street are focused on right now.