urce of supply or at tidewater, and exports consist of refined
products. The Mexican oil is largely exported in crude form to the
United States though increasing quantities are being refined within
Mexico.

The figures shown in the table for oil reserves are of course the
roughest approximations, particularly for some of the less explored
countries. However, they are compiled from the best available sources
and may serve at least to show the apparent relative positions of the
different countries at this time. Further exploration is likely to
change the percentages and add very greatly to the totals. The
significant feature of these figures is the contrast which they indicate
between distribution of reserves and distribution of past production.
Particularly do they show that the reserves of the United States, which
are more closely estimated than those of any other country, are in a far
lower ratio to past production than are the reserves in other countries.
It was estimated in 1920 that about 40 per cent of the United States
reserves are exhausted.[20]

PRESENT AND PAST PRODUCTION AND RESERVES OF OIL, BY COUNTRIES, IN TERMS
OF PERCENTAGE OF WORLD'S TOTAL

-------------------------+--------------+--------------+-------------
| | _Per cent | _Per cent
Country |_Per cent of | of total | of total
| production, | production, | oil
| 1918_ | 1857-1918_ | resources_
-------------------------+--------------+--------------+-------------
United States and Alaska | 69.15 | 61.42 | 16.26
Mexico | 12.40 | 3.80 | 10.51
Russia (southeastern | | |
Russia, southwestern | | |
Siberia, region of the | | |
Caucasus, northern | | |
Russia, and Saghalien) | 7.86 | 24.96 | 15.69
East Indies | 2.58 | 2.51 | 7.00
Roumania, Galicia, and | | |
western Europe | 2.79 | 4.07 | 2.64
India | 1.55 | 1.41 | 2.31
Persia and Mesopotamia | 1.40 | .19 | 13.52
Japan and Formosa | .48 | .51 | 2.87
Egypt and Algeria