How to replace the subsequent rows with the value right above?

[KS99]

Hi, all, 

I am always marveled at your expertise and I do appreciate your help. 

My original dataset runs as follows: 

PERSON	CUSIP6	YEAR	Diff
3	A	1987	1
3	A	1988	1
3	A	1989	1
3	A	1996	7
3	A	1997	1
3	A	1998	1
12	B	1994	1
12	B	1995	1
12	B	1996	1
12	B	1997	1
13	C	2007	1
13	C	2008	1
13	C	2011	3
13	C	2012	1
13	D	1996	1
13	D	1997	1
13	D	1998	1

The by-group here is PERSON-CUSIP6. 

The very first observation by PERSON-CUSIP6 is always 1. 

The following observations can be 1's, or an integer larger than 1. But right after it, observations regain 1's. 

What I want to create is, if a value larger than 1 appears, I want to replace the subsequent values (1's) with that value (which is larger than 1) by each by group PERSON-CUSIP6. 

So, the results will look like this: 

PERSON	CUSIP6	YEAR	Diff	Diff_k
3	A	1987	1	1
3	A	1988	1	1
3	A	1989	1	1
3	A	1996	7	7
3	A	1997	1	7
3	A	1998	1	7
12	B	1994	1	1
12	B	1995	1	1
12	B	1996	1	1
12	B	1997	1	1
13	C	2007	1	1
13	C	2008	1	1
13	C	2011	3	3
13	C	2012	1	3
13	D	1996	1	1
13	D	1997	1	1
13	D	1998	1	1

Thank you in advance! Wish you a wonderful weekend! 

KS ~ 

[Ksharp · Accepted solution]

You ask a lot of questions today. Would you like to pay us ?

data have;
infile cards expandtabs truncover;
input PERSON	CUSIP6	$ YEAR	Diff;
cards;
3	A	1987	1
3	A	1988	1
3	A	1989	1
3	A	1996	7
3	A	1997	1
3	A	1998	1
12	B	1994	1
12	B	1995	1
12	B	1996	1
12	B	1997	1
13	C	2007	1
13	C	2008	1
13	C	2011	3
13	C	2012	1
13	D	1996	1
13	D	1997	1
13	D	1998	1
;

data want;
 set have;
 retain diff_k;
 by person cusip6;
 if first.cusip6 then diff_k=.;
 diff_k=max(diff_k,diff);
run;

[PaigeMiller]

Hello, @KS99 

You already asked this question and received an answer that you marked correct. https://communities.sas.com/t5/SAS-Programming/How-to-replace-the-subsequent-rows-with-a-value-right...

Please don't ask the same question more than once.