Wacky Packages 1-16 timeline
This is the current best guess at the timeline for the release of series 1-16.

March-May 73 - 1st series (long release) 

June-Aug 73 - 2nd series (also long release) 

August/Sept 73 - 3rd series (start of the frenzie, quickened pace...) 

Oct/Nov 73 - 4th series (I've heard of 4ths given at Halloween!) 

Dec/Jan 73/74 - 5th series 

Mar/Apr 74 - 6th series (I KNOW I was in school when the 6th came out) 

May/June 74 - 7th (I remember the 7th,8th,9th in summer for CERTAIN!) 

July 74 - 8th (2nd frenzie starts, pace picks up again...) 

Sept/Oct 74 - 9th 

Oct/Nov 74 - 10th 

Nov/Dec 74 - 11th (Boom, Boom, Boom, these sets ran right together) 

Jan 75 - 12th ("Tues, Jan 28" date written on the 12th sheet auctioned by topps in July, 2002) 

Feb/Mar 1975 - 13th (Dated 1975 now) 

Apr/Jun 75 - 14th 

July+...1975 - 15th... (these took longer & lasted longer, and we all thought it was over) 

Late 1977 - 16th (very low distribution & short release time, sticker copyright
                  was 1976, but the shipping cases say 1977)