Michigan secretary of state claims a million more registered voters than eligible voters. Explain.

Michigan was one of the six battleground states where Trump held a significant lead until midnight of election day, when a sudden surge in Biden votes supposedly gave Biden the win.  Odd.  But the official record shows something that seems to unequivocally show fraud:

The state's secretary of state reported 8.1 million registered voters for the presidential election.  (Source: https://mvic.sos.state.mi.us/VoterCount )

Now, census estimates show Michigan's population in 2020 was 9.83 million.  About 2.34 million of those are under 18 (1.141 million females, 1.194 million males), and thus not eligible to vote.  
(Source https://suburbanstats.org/population/how-many-people-live-in-michigan)(data at bottom)

If those numbers are close, that leaves 7.5 million *eligible voters.*  Yet state says 8.1 million *registered voters*.  Not even close.  WTF?

Further, not everyone who's eligible to vote is registered to vote.  If we generously assume that an outlandish 95% of *eligible* voters were registered, the likely number of registered voters in MI drops more, to around 7.125 million.  

But again, the *official* number reported by the Sec of State's office claims the state has 8.1 registered voters--almost a million more than would appear possible.

I'd love to hear the state's SoS--a Democrat female Hahvahd Law grad--explain this.

Wait, let me guess:  "Computer glitch, and it happened a million times before we noticed and fixed it.  And the fix was done by a commercial IT firm so we can't tell you what part of the code was to blame."  
   Or "The number of registered voters posted on our website is wrong.  It was posted by an new, untrained, low-level employee.  Who we won't name because we don't disclose personnel matters."  

   Or "The organization you cited, "suburbanstats.org", got the number of children under 18 in our state wrong.  They said 2.34 million but the real number is 1.34 million.  Just a data-entry error. So, problem solved."

   Or "After the election we had a HUGE surge in the number of people registering to vote.  On election day of 2020 we only had 7.1 million registered voters.  Problem solved."

One way to show what's true (or expose a lie) is:  The corrupt SoS made a unilateral decision to mail absentee-voting applications to every registered voter.  Someone should ask her how many such applications she claims to have mailed out.  That would resolve the question one way or the other, eh?