Below is one option using Col Cumulative Sum() with comparison
Names Default To Here(1);
dt = New Table("Untitled",
Add Rows(14),
Compress File When Saved(1),
New Column("Column 1",
Character,
"Nominal",
Set Values(
{"No", "No", "No", "No", "Yes", "No", "No", "No", "No", "No", "Yes",
"No", "No", "No"}
)
),
New Column("Column 2",
Numeric,
"Continuous",
Format("Best", 12),
Set Values([1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3])
)
);
dt << New Column("Series", Numeric, Continuous, Formula(
Col Cumulative Sum(:Column 1 == "Yes") + 1
));
-Jarmo