In 2002, at about the same time (just before Amelia Island), this was the combined williams' sisters record:
Serena - 14/2
venus - 17/3
=> a combined 86% winning ratio
Serena - Scottsdale, Miami
Venus - Paris, Antwerp
Within this time period, they had losses to Meghann, Patty s., monica and sadrine.
In 2003, within the same time period,
Serena - 21/1
venus - 12/2
=> a combined 91% winning ratio
Serena - AO, Miami, Paris
Venus - Antwerp
Within this time period the only people who beat the sisters were only Meghann and Justine.
Yes, that shows compared to the last year at similar time, their domination was really broken.