Analyze and default_statistics_target

I was under the impression that the default_statistics_target was a
percentage of rows to analyze.  Maybe this is not the case?

I ran an analyze during a "quiet point" last night and for a few of my
large tables, I didn't get what I consider a reasonable sampling of
rows.  When running with "verbose" enabled, it appeared that a maximum
of 240000 rows were being analyzed, including on tables exceeding 4-8mm
rows.  My default_statistics_target = 80.

Shouldn't I be analyzing a larger percentage of these big tables?

What is the unit-of-measure used for default_statistics_target?

Thanks in advance,
AJ