] The most common female names in 17th - early 19th century were, in order of popularity

] 1)Elizabeth
] 2)Catherine
] 3)Mary
] 4)Anne
] 5)Margaret
] 6)Jane

I just had to take the opportunity to wonder if the use of Lydia's name in P&P might be a bit of judicious foreshadowing on JA's behalf of Lydia's future ;)