Sox to Bond Ratio

I guess there is no one to blame
We're leaving ground
Will things ever be the same again?
It's the final countdown
--Europe

Never heard of the SOX to Bond ratio, nor do I know what comprises the 'bond' component. But the ratio of SOX (Philly Semiconductor Index) to a broad measure of bonds suggests some froth in the semis.

Last time the SOX:Bond was this high: the dot.com peak.