All the raw data driving those graphs is available through this command:
$ adb shell dumpsys netstats detail full
"dev" and "xt" stats are two different ways of measuring the overall device data usage, and they should be almost identical. I'd lean toward using "xt" stats for analysis.
The "uid" stats are broken out per-UID on the device, and you can find a quick UID mapping in /data/system/packages.list. You can ignore UID records with tag != 0x0, since they are already rolled up into the 0x0 records, and the tags values are really only useful to the developers of those apps.
By default, overall stats are recorded into one-hour buckets, and UID stats are recorded into two-hour buckets.
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