Hmmm...lessee...I'm coming up on 30 years since I graduated from high school... In no particular order, I've learned and written code in the following languages:

1. Algol
2. TUTOR
3. C
4. Pascal
5. FORTRAN
6. COBOL
7. Z80 assembler
8. PDP-11 assembler
9. BASIC
10. awk
11. (k)sh
12. csh
13. Perl
14. Lisp
15. Pilot
16. CourseWriter
17. DOS batch
18. Java
19. SQL (multiple dialects)
20. HyperTalk
21. Postscript
22. C++
23. (Web)Focus
24. PMS
25. Forth
26. JavaScript
27. Business Objects (I think)
28. ...

I may have left a couple out... OK, so it's not quite one per year in the long run, but it comes pretty close...