What was the "boom"?
Electricity
1929
Most of the houses have electricity
1918
Only few house have electricity
More buildings
New York City
New economy
Increase
Cars
Telephone
Radio
Fridges
The new roads
Gave a rise to a new truck industry
1929
3,5 million truck
1919
1 million truck
Airlines
1930
New aicraft companies flew 162,000 flights a year