Spoiler warning: Quest and/or game spoiling details follow.
Lottery Ticket Statistics
10551 tickets used, 132 winning tickets (1.25%)
To get a full return for the money lost by depositing them for tickets, you'd have to sell each ticket for 39965.91 gp.
Once you have opened 500 blank Lottery Tickets you will receive the Jinx achievement.
Spoiler ends here.