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| 1st | 2nd - Region | 3rd+4th - Code - POP | 5 - Peer Relationship | |
|---|---|---|---|---|
| 5 | 1 - North West (Superior area) | 2 digit POP code, unique per region. 01-99 | 1 | Transit |
| 2 - North Central (Ashland area) | 2 | Peer - Public (IX) | ||
| 3 - North East (Marinette area) | 3 | Peer - Private (PNI) | ||
| 4 - West (Minneapolis area) | 4 | Peer - Research | ||
| 5 - Central (Wausau area) | 5 | Cache | ||
| 6 - East (Green Bay area) | 7 | Aggregate | ||
| 7 - South West (Platteville area) | 8 | Customer | ||
| 8 - South (Madison area) | ||||
| 9 - South East (Milwaukee area) | ||||
| Examples | 2381:51011 | Transit from Northwest Region, Pop # 01 | ||
| 2381:59342 | Peer from South East region, pop # 34 | |||
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