Britney Spears Ticket Sales -- Through the Roof

There are conflicting reports out about ticket sales for Britney Spears' Vegas concerts ... some are saying sales are disastrously poor ... Brit's people are saying "it's the best-selling show in the history of Vegas." TMZ now has the numbers, and it's pretty clear -- Britney is about to own Vegas.

Britney will be performing 48 shows a year for the next 2 years -- according to the contract obtained by TMZ. Tickets are available now for the first 16 shows. We've been on dozens of calls with StubHub, Ticketmaster and Planet Hollywood's box office among others ... and here's what we're told.

For the first 16 shows ... a total of 73,600 tickets were up for sale. The number of tickets actually sold is impressive -- 70,242.

Of the available, remaining, 3,358 tickets, 2,887 are in the nosebleed section.

We can't vouch for this being the best selling show ever in Vegas, but it's definitely up there.