[SYSTEM]
You are answering a single information-extraction question. Use ONLY the supplied source material. Do not use prior knowledge. Give a clear, concrete answer with the specific number, name, year, or value asked for.

[USER]
--- SOURCE ARTIFACT (M3-L4) ---
# Table 033 — Table 15. Station Count by Year by Month

PDF page: 36

```csv
Year,Jan,Feb,Mar,Apr,May,June,July,Aug,Sep,Oct,Nov,Dec,Total
1950,27,5,13,42,45,44,91,66,69,113,51,54,620
1951,19,33,23,25,15,0,0,51,81,93,44,0,384
1952,0,1,58,56,31,0,0,83,81,85,50,0,445
1953,39,0,44,50,0,0,4,135,161,28,29,0,490
1954,37,48,20,24,2,39,0,82,73,107,60,18,522
1955,0,0,49,0,39,17,51,77,80,135,69,0,517
1956,0,0,0,0,0,0,2,80,92,90,74,53,391
1957,0,0,0,0,0,0,0,0,47,75,38,0,160
1958,0,57,62,73,76,0,0,54,71,0,0,0,393
1959,4,58,87,94,76,48,21,83,100,85,55,0,711
1960,0,34,58,81,47,4,67,78,84,119,94,0,666
1961,0,0,82,79,0,0,22,89,62,103,104,55,596
1962,0,11,116,0,0,0,18,52,66,78,78,38,457
1963,0,0,0,0,64,62,3,69,57,56,77,0,388
1964,0,0,0,0,48,57,2,77,68,76,77,62,467
1965,0,0,0,20,6,0,34,58,72,85,57,5,337
1966,0,0,0,25,9,198,141,0,145,168,136,0,822
1967,0,0,49,157,77,108,49,29,91,139,143,57,899
1968,104,100,156,196,63,158,11,157,144,72,173,43,1377
1969,133,29,0,0,154,39,23,107,62,107,108,36,798
1970,33,108,0,123,65,80,0,53,49,133,88,0,732
1972,0,0,0,133,39,87,0,20,122,75,121,0,597
1973,0,54,78,42,146,106,0,83,0,149,59,2,719
1974 1975,0 0,0 173,0 0,90 72,55 4,93 89,0,0,0,89 131,157 51,0 0,484 700
,,,,,,,0,44,136,,,,
1976,0,0,0,97 85,49,142,0,0,72,75 98,164,0 0,599
1977,71,158,54,,0,87,0,0,0,,158,,711
1979,45,130,0,68,0,0,0,0,,0,134,0,377
1980,11,169,0,0,0,,0,,0,,,0,
,,,,,,0,,0,111,71,76,,438
1981 1982,0,170,55,118 0,0 0,0 0,0,0,0,122,82,53,600 544
1983,0 0,237 178,53 32,0,0,0,0 0,101,0,153 97,0 105,0 0,451
,0,242,24,0,,0,0,0 0,39 101,0,117,12,496
1984,,,9,0,0,0,66,55,140,0,0,0,503
1985,0,233,,,0,,,,,,,,
1986,0,51,72,0,0,23,0,54,56,104,0,0,360
1987,0,26,81,80,0,0,16,1,0,0,0,0,204
1988 1989,0 0,0 0,56 0,51 47,30 75,0 0,0 0,0 0,0 94,120 57,0 0,0 0,257 273
Total,576,2649,1349,2043,1291,1653,621,1934,2728,3288,2876,554,21562
```

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Question:
The NOAA oceanographic survey database (Table 15) records the count of sampling stations by year and month. Data are available for September 1970 and September 1972. No September 1971 entry is shown. Estimate the number of September stations in 1971 by linear interpolation between the 1970 and 1972 September counts.

Answer concisely. Cite the row/cell/section you used. State your final numerical answer clearly.