(Lucas Jackson/Reuters)

More than 150 people have been taken to St. Louis county jail since the shooting of Michael Brown on Aug. 9 sparked unrest in Ferguson, according to county officials. The vast majority of the arrests — 78 percent — took place within the last four days. As many as 80 percent of those arrested were charged with "failure to disperse" amid the street protests.

It's important to note that this is only a partial picture. This data comes from the St. Louis County Executive's Office, which has been clear that people taken to municipal jails — rather than county jails — are not included in the data.

There's also another important question. As you can see, the number of arrests in the chart above dips to just one on Aug. 14 and 16, and falls completely to zero on Aug. 15. If that seems low, it is possible that arrests made on those days were funneled to municipal jails. I've reached out to St. Louis County officials for an explanation, and I'll update this post if and when I hear back.

With no end to the demonstrations in sight — and with some questions still unresolved — expect closer examination of this data.