Table:
text: Dancing with the Stars (U.S. season 10)
Ratings
Ratings
Episode_Number Episode Original_Airdate Rating Share_ Rating_Share_18_49 Viewers_millions Weekly_Rank
10.16 Week 9, Part 1 May 17, 2010 12.1 19 4.1/11 19.04 1
10.17 Week 9, Part 2 May 18, 2010 8.6 14 2.5/7 13.19 13
10.18 Week 10, Part 1 May 24, 2010 12.6 21 4.0/12 19.36 3

Question: How many million viewers watched episode number 10.18 during the ratings period of Dancing with the Stars (US season 10)?