The data cited isn't really accurate.
According to the U.S. Department of Agriculture:
The program operated by permitting people on relief to buy orange
stamps equal to their normal food expenditures. For every $1 worth of
orange stamps purchased, 50 cents worth of blue stamps were received.
Orange stamps could be used to buy any food. Blue stamps could only be
used to buy food determined by the Department to be surplus. . . .
Over the course of nearly 4 years, the first FSP reached approximately
20 million people at one time or another in nearly half of the
counties in the United States, peak participation was 4 million, at a
total cost of $262 million.
A slightly more in-depth analysis can be found here:
The first Food Stamp Program came about as a result of the need to
distribute excess farm commodities during the Great Depression. After
World War I, exports to Europe decreased and farm prices continued to
drop during the 1920s. Between 1929 and 1932, commodity prices fell
more than 50%. Although farmers were producing bumper crops of wheat,
they still had less than half the income of non-farm families. In 1933
about 25% of Americans lived on farms as compared to the 2% of the US
population living on farms today (7). As part of President Franklin
Delano Roosevelt’s New Deal, Congress passed the Agricultural
Adjustment Act of 1933. The purpose of the act was to provide farmers
with more income and distribute food to the needy. This mission was
carried out by the Federal Surplus Relief Corporation, which became
the Federal Surplus Commodities Corporation in 1935. By 1938, the
federal government was purchasing, transporting, storing, and
distributing massive amounts of food to state and local relief
agencies. Although most citizens supported transfer of surplus foods
to the needy, some criticized the Federal Surplus Commodities
Corporation because the process duplicated services being provided by
the private wholesale and retail grocery industries (8). To address
these concerns, Secretary of Agriculture Henry Wallace had the idea
for the first Food Stamp Program.
On May 16, 1939, Mabel McFiggin of
Rochester, NY, became the first relief recipient to purchase food
stamps. Eligible people could spend cash they ordinarily used for food
to purchase orange stamps. As a bonus, they received $0.50 worth of
free blue stamps for every dollar they spent. Participants could use
the orange stamps to buy any food; however, blue stamps could only be
spent for foods the USDA had declared as surplus (7). The idea behind
requiring needy families to purchase stamps was that “income normally
spent on food would not be diverted to nonfood items owing to the
subsidy embodied in the free blue stamps” (9). During the 4 years of
the program, the top-20 blue stamp surplus foods ranked in descending
order were dry beans, flour, corn meal, eggs, fresh vegetables, hominy
grits, apples, butter, oranges, dry prunes, pears, pork, raisins,
grapefruit, potatoes, lard, rice, dry onions, peaches, and plums (8).
Both the orange and blue stamps were printed in $0.25 denominations
and during the course of the 4 years from May 1939 through March 1943
were distributed in nearly half the counties in the country, covering
an area where more than 60% of the population lived. Major cities were
targeted and people in New York City received 14.4% of the total
subsidy in early 1942. Peak participation in the first Food Stamp
Program was 4 million people, although over the 4 years nearly 20
million citizens received benefits (8).
The only state that did not receive food stamps was West Virginia.
This was due to a provision in the state’s legislation that did not
permit exemption of blue stamp sales from tax. To address the
depression in that state, West Virginia received other types of direct
assistance rather than food stamps.
Joseph Mutolo was the first retailer to redeem the stamps. Like other
grocers, he converted the stamps into cash through food wholesalers or
banks. There were reports of illegal trafficking in food stamps and
the first retailer caught violating the program was Nick Salzano in
October 1939 (7).
During the 4 years that the first Food Stamp Program lasted, cost to
the federal government was $262 million (7). Adjusting for inflation
that would amount to a 4-year program costing about $3.7 billion today
(10). With never more than 1,000 federal employees engaged in the plan
operations, administrative costs of that initial program were only
about 3% of total funds spent. Thus, much of the operational burden
was carried by state relief agency employees who certified households
as eligible and largely ran the program (8). Milo Perkins, the first
Food Stamp Program administrator stated, “We got a picture of a gorge,
with farm surpluses on one cliff and undernourished city folks with
outstretched hands on the other. We set out to find a practical way to
build a bridge across that chasm.” With World War II came a booming
economy that largely erased the unmarketable food surpluses and
widespread unemployment of the Great Depression (7). The first Food
Stamp Program ended in spring 1943.
The ultimate source for all the modern accounts of the number of beneficiaries is a 1947 journal article which is closed access.
Thus, by design, the biggest benefit you could receive was a third of your total, post-benefits food expenditures. And, if you were really poor, and could only afford a small amount of food, you couldn't afford to buy many food stamps. The program bore little similarity to the modern food stamp program which started in 1961 and was revamped significantly in 1963.
The plan was also carried out as a price management measure for food at a time when food prices were artificially low due to a demand shortage, leading to on oversupply of perishable food inventories.
Also, the average number of beneficiaries at one time was less than 4 million during that four year period, so the average amount of time that any given person received benefits was less than ten months, probably significantly less.
As a result, the 1939-1943 data for the program (it really started in 1939 not 1938) isn't comparable to the modern Food Stamp program data on an annualized basis.