The C spectrum used in some calculations is this:
Here is a table of the values:
Wavelength[nm] Intensity
380 31.3
385 37.9
390 45.0
395 52.4
400 60.1
405 68.2
410 76.5
415 85.0
420 93.2
425 100.5
430 106.7
435 111.8
440 115.4
445 117.2
450 117.8
455 117.4
460 116.9
465 117.1
470 117.6
475 117.8
480 117.7
485 116.7
490 114.6
495 111.0
500 106.5
505 101.6
510 97.2
515 93.8
520 92.0
525 91.9
530 93.1
535 94.9
540 97.0
545 98.7
550 99.9
555 100.3
560 100.0
565 98.9
570 97.2
575 95.1
580 92.9
585 90.6
590 88.5
595 86.6
600 85.2
605 84.4
610 83.9
615 83.8
620 83.7
625 83.6
630 83.6
635 83.4
640 83.4
645 83.6
650 83.8
655 83.8
660 82.5
665 82.8
670 82.0
675 81.0
680 79.8
685 78.1
690 76.2
695 74.3
700 72.5
705 70.6
710 68.8
715 66.9
720 64.9
725 63.0
730 61.2
735 59.6
740 58.4
745 57.2
750 56.2
755 55.6
760 55.2
765 55.1
770 55.3
775 55.6
780 56.1