How many background track types are available for Streaming synthetic voices?

The following 38 background tracks are currently available:

1. (Classical) Lucky Pets

2. (Classical) Figure It Out

3. (Classical) Pizzi Caper

4. (Classical) Creating A Masterpiece

5. (Club/Electronica) Give Up The Night

6. (Club/Electronica) Light Parade

7. (Country) City Girl Country Boy

8. (Country) Keep Thinking Keep Drinking

9. (Country) Soak Up The Sunshine

10. (Country) Twang Time

11. (Dance) Shine

12. (Folk) Sunshine In Spring

13. (Folk) Cushion boogie

14. (Hip Hop) Booty Booming

15. (Hip Hop) Barbaric Splendor

16. (Hip Hop) Massive Mama Jama

17. (Hip Hop) Crowd Pleaser

18. (Indie) Snappy And Happy

19. (Indie) Blueprint Design

20. (Jazz) One More Time

21. (Jazz) Walking in Birdland

22. (Jazz) Diggy Diggy Do

23. (Latin) In the Calle

24. (Latin) Con Tumbao

25. (Latin) Como Animales

26. (Percussion) Bucket Boys

27. (Percussion) Technicolor Dreams

28. (Pop) Endless Summer

29. (Pop) Festive Youth

30. (Pop) Fun Starts Here

31. (Pop) Plug and Play

32. (Pop) Sandbox

33. (Pop) Lets all Go Together

34. (R&B) Gotta Have It

35. (Rock) More Cowbell

36. (Rock) Fresh Find

37. (Rock) Blood Money

38. (World) An Odd Bird