Another one I can'f figure out myself...

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input str9 ddate byte run_no str7 name byte(rating maxlr2)
"14-Jul-16"  1 "Zymyran" 24  .
"04-Aug-16"  2 "Zymyran" 69 24
"30-Aug-16"  3 "Zymyran" 74 69
"13-Sep-16"  4 "Zymyran" 77 74
"29-Sep-16"  5 "Zymyran" 83 77
"21-Oct-16"  6 "Zymyran" 87 83
"11-Nov-16"  7 "Zymyran" 81 87
"02-May-17"  8 "Zymyran" 87 87
"20-May-17"  9 "Zymyran" 43 87
"16-Jun-17" 10 "Zymyran" 82 87
"18-Aug-17" 11 "Zymyran" 89 82
"25-Aug-17" 12 "Zymyran" 86 89
"06-Sep-17" 13 "Zymyran" 90 89
"10-Oct-17" 14 "Zymyran" 91 90
end
Looking here to create a new variable maxlr2 (included here for clarity)
Basically I need maxlr2 to return the maximum value found in the two previous 'run_no' from the 'rating' column.

Thank you