Data more;
do month = 1 to 12;  
do year = 1994 to 1997;
input sales2  @@; sales2 = round(sales2/1000000,.01);
date = intnx('month',mdy (month,1,year),5); 
format date monyy.; 
output; end; end;   
datalines;
7046904256 	7647959169 	9480161812 	 9659439910 
6981728317 	7658070382 	8964028737 	 9583176482 
6937376730 	7718830461 	8658258814 	 9476522848 
7211616880 	7601791200 	9002886208 	 9767938174 
7365763115 	7435871521 	9678629215 	 9781508705 
6758181964 	8028347172 	9458391776 	 9495267559 
8533735305 	9084118466 10234714286 	10679094670 
6383650956 	7660381820 	9003095665 	 8523476102 
6389704985 	7340004790 	8390674070   9229974759 
7392635878 	8605579947 	9631012865 	10127725553 
7766108264 	9509181607 	10002286021 10424964348 
7824996310 	9062730301 	9553813753 	10013122345 
 ;
 proc sort; by date; 
 data both; merge sales more; by date; 
proc print; run; 
proc gplot; plot (sales sales2)*date/overlay; 
run; 

Data yr1998_9; 
input sales2; month+1; 
sales2 = round(sales2/1000000,.01);
date = intnx('month',mdy (month,1,1998),5); 
datalines;
11011054676
 9790289828
11440260326
10800545622
10519587943
10271752729
11458124481
 9268196647
 9396753637
11351596003
10322198042
10622979069
 ;
Data yr1999_0; 
input sales2; month+1; 
sales2 = round(sales2/1000000,.01);
date = intnx('month',mdy (month,1,1998),5); 
datalines;
11,256,858,608
10,987,565,227