Butterick 3763 vintage sewing pattern, dated 1970s. 

Misses' Dress, Top & Pants.

Loose-fitting A-line dress or top with side slits has applied front detailing with neckline split, pointed collar, dropped shoulders, wide sleeves with turned-back cuffs, and topstitch trim. Self tie or purchased belt. Straight-legged pants darted into waistband have back zipper closing. 

Size   12:

Bust   34 inches / 87 cm

Waist 26 1/2 inches / 67 cm

Hip    36 inches / 92 cm

Pattern is uncut and factory folded. Envelope is intact, with paper spotting down one side. 

More '70s patterns here:

http://allthepreciousthings.com/collections/1970s