Calculate Gain Chart Using SQL in Oracle

The following script calculates the gain chart based on score and payment_ind (target variable, payment or non payment).  The mod function is to reduce the number of data points in the gain chart

with  tbl2 as
(select a.*, row_number() over(order by score desc ) risk_rank from tbl_testing_data a),
tbl3 as
( select a.*,
count(1) over(order by risk_rank) total_num,
sum(case when payment_ind='Y' then 1 else 0 end ) over(order by risk_rank) total_bad,
count(1) over(order by risk_rank)/count(1) over() pcnt_tot,
sum(case when payment_ind='Y' then 1 else 0 end ) over(order by risk_rank)/ sum(case when payment_ind='Y' then 1 else 0 end ) over()
pcnt_bad
 from tbl2 a
)
select * from tbl3 where mod(risk_rank,100)=1 order by risk_rank;