I'd say 1975 or 1976 (I think it's an XL-100):

http://www.wavesllc.com/images/colortable0003.JPG

I thought I read somewhere that this set was a 1974, so I'll guess that:

http://www.wavesllc.com/images/colortable0001.JPG

I think that's a B&W set from the mid '70's.

The bottom link is a late '70's Sharp Linytron color set.

I think that's a B&W set from the mid '70's.

My 1974 RCA XL-100 is very similar to this set, and it's color (at least that's what the seller said, still having it fixed since there was no picture or sound when I got it).

Those do look similar to a color set; but, this one is a 15" B&W. It has a push on/off power switch and the three knobs at the bottom are for brightness, contrast, and volume. In the mid '90's, I fixed one just like it for an elderly lady who claimed that she'd never owned a color TV and didn't want to own a color TV. Her TV worked very well after I replaced a bad power supply filter cap.