In 1970, LEGO released 2 Duplo sets in the subtheme Basic Set, all of these sets have been retired. For that year, the total price of all retail sets cost $4, today those sets are valued around $94, a growth of 2402%.
Most valuable 1970 LEGO Duplo set
512 Building Set $50.25
Largest 1970 LEGO Duplo set
513 Building Set 29 pieces
2 sets

512 Building Set

Theme / Subtheme Duplo / Basic Set
Year 1970
Pieces 20
Availability Retired
512 LEGO Duplo Building Set
Retail $1.25
Value $50.25
Growth  +3920.0%
Annual growth 8.1%

513 Building Set

Theme / Subtheme Duplo / Basic Set
Year 1970
Pieces 29
Availability Retired
513 LEGO Duplo Building Set
Retail $2.49
Value $43.33
Growth  +1640.2%
Annual growth 5.2%