Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Vehicle | EPA rated All-electric range | EPA rated combined fuel economy | Alaska ( Juneau ) | California (San Francisco) | Mid-Atlantic South (Washington, D.C.) | U.S. national average electric mix | Southeast (Atlanta) | Midwest (Des Moines) | Rocky Mountains (Denver) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Mitsubishi i-MiEV | mi (km) | 112 mpg-e (30kW-hrs/100 miles) | 80 g/mi (50 g/km) | 100 g/mi (62 g/km) | 160 g/mi (99 g/km) | 200 g/mi (124 g/km) | 230 g/mi (143 g/km) | 270 g/mi (168 g/km) | 290 g/mi (180 g/km) |
| Ford Focus Electric | mi (km) | 105 mpg-e (32kW-hrs/100 miles) | 80 g/mi (50 g/km) | 110 g/mi (68 g/km) | 170 g/mi (106 g/km) | 210 g/mi (131 g/km) | 250 g/mi (155 g/km) | 280 g/mi (174 g/km) | 310 g/mi (193 g/km) |
| BMW ActiveE | mi (km) | 102 mpg-e (33kW-hrs/100 miles) | 90 g/mi (56 g/km) | 110 g/mi (68 g/km) | 180 g/mi (112 g/km) | 220 g/mi (137 g/km) | 250 g/mi (155 g/km) | 290 g/mi (180 g/km) | 320 g/mi (199 g/km) |
| Nissan Leaf | mi (km) | 99 mpg-e (34kW-hrs/100 miles) | 90 g/mi (56 g/km) | 120 g/mi (75 g/km) | 190 g/mi (118 g/km) | 230 g/mi (143 g/km) | 260 g/mi (162 g/km) | 300 g/mi (186 g/km) | 330 g/mi (205 g/km) |
| Chevrolet Volt | mi (km) | 94 mpg-e (36kW-hrs/100 miles) | 170 g/mi (106 g/km) (1) | 190 g/mi (118 g/km) (1) | 230 g/mi (143 g/km) (1) | 260 g/mi (162 g/km) (1) | 290 g/mi (180 g/km) (1) | 310 g/mi (193 g/km) (1) | 330 g/mi (205 g/km) 1) |
| Smart ED | mi (km) | 87 mpg-e (39kW-hrs/100 miles) | 100 g/mi (62 g/km) | 130 g/mi (81 g/km) | 210 g/mi (131 g/km) | 260 g/mi (162 g/km) | 300 g/mi (186 g/km) | 350 g/mi (218 g/km) | 380 g/mi (236 g/km) |
Question:
What was the US national average electric mix rating for the vehicle that was rated 280 g/mi (174 g/km) in the Midwest?
Answer:
210 g/mi (131 g/km)