st: CDF and distplot

["Eric B." <ericbstata@gmail.com>]

Dear Statalist users,

I need help plotting a cumulative distribution function. After many 
attempts with other commands, I am using the user-written - distplot - 
as it allows flexibility in terms of configuring the look of the lines 
and graph.

The variable I want to plot assumes integer values between 0 and 20. I 
need a cdf that plots two lines in the same graph by gender. While there 
are observations from 0 to 20 in the female sub-group, there are not 
observations higher than 10 for the male subgroup. The cdf line for the 
male subgroup reaches 100% at variable-value 10 and the line stops 
there. The cdf for the female subgroup continues up to 20. I would like 
both lines to continue through to 20, since is the range of the original 
data.

In case I was not too clear, I have adapted the auto.dta data to show 
this issue and made the data on prices as an integer:

sysuse auto.dta, clear
gen thousand=3 if price < 4000
replace thousand=4 if price < 5000 & price >=4000
replace thousand=5 if price < 6000 & price >=5000
replace thousand=6 if price < 7000 & price >=6000
replace thousand=7 if price < 8000 & price >=7000
replace thousand=8 if price < 9000 & price >=8000
replace thousand=9 if price < 10000 & price >=9000
replace thousand=10 if price < 11000 & price >=10000
replace thousand=11 if price < 12000 & price >=11000
replace thousand=12 if price < 13000 & price >=12000
replace thousand=13 if price < 14000 & price >=13000
drop if foreign==1 & thousand>9
distplot thousand, over(foreign)

So I would like the cdf line for foreign to continue at 100% up to 13 
(which is the maximum value in this dataset).

All help on how to solve this is appreciated. Thanks.
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