Plastic parts and insulation have helped to improve their energy efficiency by 30 to 50 percent since the early 1970s.
(Plastic parts and insulation; have helped; to improve their energy efficiency by 30 to 50 percent since the early 1970s) Context(Plastic parts and insulation have helped,List([0, 40))):(Plastic parts and insulation; have helped to improve; their energy efficiency)
Plastic parts and insulation have helped,List([0, 40))
Plastic parts and insulation Plastic parts and insulation
have helped have helped to improve
to improve their energy efficiency by 30 to 50 percent since the early 1970s
their energy efficiency