In analyzing the issue dates of plant patents, I was surprised to see
that there were many months where there weren't any plant patents
issued.
| Year | Months Without Plant Patents |
|---|
| 1931 | September December |
| 1932 | January June |
| 1933 | August December |
| 1934 | July |
| 1935 | April |
| 1936 | July |
| 1937 | May |
| 1938 | March July December |
| 1939 | May |
| 1944 | November |
| 1945 | January May July September |
| 1946 | February March |
| 1947 | February |
| 1948 | June |
| 1970 | February March May |
| 1971 | May June July September October November December |
| 1972 | January February September October November |
| 1973 | April October December |
| 1974 | July |
| 1979 | December |
| 1980 | December |
| 1981 | December |
| 1986 | September |
| 1987 | June July August November |