Over the last 25 years, the 'big six' teams have dominated the FA Cup final. They've won 23 out of 25 between them, with the only exceptions being Portsmouth in 2008 and Wigan in 2013.
Both of the non-big six sides that have won the FA Cup over this period are now League One sides.
Chelsea have been in 10 of the last 25 finals, winning 7 and losing 3. The only non 'big six' opponent to beat Chelsea in an FA Cup final was Sheffield Utd in 1915.
Wigan beat Man City in 2013 but the previous time a non 'big six' side beat a 'big six' side in the final before that was Everton in 1995. It's pretty rare. Before Everton, there were a couple in the 1980s (Coventry and Wimbledon).
Of course, our last three FA Cup finals were all defeats to 'big six' teams.
The FA Cup final is typically the most watched UK match domestically and worldwide with approx. 400 million people tuning in.