Dear all,
How can i transform the data structure below
Code:
* Example generated by -dataex-. For more info, type help dataex
clear
input str6 var1 double(var2 var3 var4 var5)
"year" 1 2 3 4
"gdp"  1 1 1 1
"year" 5 6 7 .
"gdp"  2 2 2 .
end

. list

     +----------------------------------+
     | var1   var2   var3   var4   var5 |
     |----------------------------------|
  1. | year      1      2      3      4 |
  2. |  gdp      1      1      1      1 |
  3. | year      5      6      7      . |
  4. |  gdp      2      2      2      . |
     +----------------------------------+
I want to combine the first and second row with third and fourth row,just like below

    +------------+
     | year   gdp |
     |------------|
  1. |    1     1 |
  2. |    2     1 |
  3. |    3     1 |
  4. |    4     1 |
  5. |    5     2 |
     |------------|
  6. |    6     2 |
  7. |    7     2 |
     +------------+
Any help will be appreciated.

best
Raymond