Television Audience Analysis of the Six Nations suggests that while the peak audience increased, the average audience over the entire tournament dropped.
Year on Year comparison: 
Most watched games of 2013: 
Some interesting titbits:
Cumulative audience (based on % audience duplication) – 662,639 viewers
The Scotland v Italy game on the 9th of February attracted the highest viewership. 233,055 tuned in to watch this game. 30% of all viewers that watched this game, watched it without anybody else in the room (solo viewership). Female ‘solo viewership’ was also fairly high at 12.5%.
All information courtesy of RepucomSA
