Specyfing paths with percentages unit.

I've got a question with probably obvious answer, but I can't find
it...

I want to draw a simple path, but using percentages as units.

I've got svg element of 380x190 size. And I've got path like this one:

        <path id="path_one" fill="url(#gradient_one)"
              d="M  136,183
                 C  205,190  358,138  368,116
                 C  377, 91  380, 59  281, 22
                 C  245,  9   98,  0   62, 13
                 C   10, 32    0, 65    6, 87
                 C   12,108   47,175  136,183
                 z"
        />

It works perfect. But when I convert path coordinates to percentages,
like this:

d="M 36%,96% C 54%,100% 94%,73% 97%,61% C 99%,48% 100%,31% 74%,12% C
64%,5% 26%,0% 16%,7% C 3%,17% 0%,34% 2%,46% C 3%,57% 12%,92% 36%,96%
z"

Then it doesn't work at all - nothing renders.

I can easily draw a line using percentage units:
<line x1="10%" y1="90%" x2="100%" y2="90%" stroke="red" stroke-
width="2" />

But the same doesn't work with "path" element - why?


P.S.
Sorry if I hit the wrong group - is there any more suitable then this
one?