How to interpret Site Frequency Spectrum? (SFS, allele frequency spectrum)

Question

[jaredmeyers]

I have a Site Frequency Spectrum graph with K value on the x-axis and Number of Variants on the y-axis. I'm not sure what the graph means by K value. The shape of the graph is a shallow "U" with a high number of variants at or around 0 K value.

I could probably figure out how to read the graph if I just know what it meant by K value!

Thanks!

[seta]

please show your graph