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:
| Tramway | Country | City | Height of pylons | Span width,\nleaning straight line | Span width,\nhorizontal measurement | Height of cable over ground | Year of inauguration | Notes |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Peak 2 Peak Gondola | Canada | Whistler | 65m | 3024 m | 3019 m | 436 m | 2008 | 3S Aerial Tramway constructed by Doppelmayr |
| Hut of Regensburg Material Transport Aerial Railway | Austria | Falbeson | ? | ? | ? | 430 m | ? |  |
| Vanoise Express | France | Vanoise | none | 1850 m | 1800 m | 380 m | 2003 |  |
| Aiguille du Midi | France | Chamonix | none | 2867 m | 2500 m | ? | 1955 | 2nd Section |
| Vallee Blanche Aerial Tramway | France | Mont Blanc | none | 2831 m, 1684 m | span is almost horizontal | appr. 300 m | 1958 | Rock anchored support structure |
| 3S Aerial Tramway | Austria | Kitzbühel | 0 m, 80m | 2507 m | ? | 400 m | 2004 |  |
| Sandia Peak Tramway | USA | Albuquerque | 70.7 m, 21.33 m | 2353 m | ? | 274 m | 1966 |  |
| Feldmoos-Chli-Titlis Aerial Tramway | Switzerland | Titlis | 37.6 m | 3476,2 m | ? | ? | 1979 | Temp. site tramway, demolished in 1986 |
Question:
at least how many aerial tramways were inaugurated after 1970?
Answer:
4