st: width() invalid error when using a local macro to loop over years

[Diederik van Liere <Diederik.vanLiere@rotman.utoronto.ca>]

Dear statalist members, 

I would like to dynamically generate dates for a simple macro. The dataset contains two variables: experience and date. Experience is a simple count variable and date is the date of observation. I would like to generate a number of histograms for different years.  The current code to do this looks:


forvalues year = 2001(1)2011 {
	histogram experience if date==mdy(1, 30, `year'), discrete percent 
}

However, this does not work. Stata raises the following error:
	width() invalid -- invalid number, outside of allowed range.  
I am not quite sure why this is the case, wrapping the year variable like "`year'" does not solve the problem either. 

Any suggestions on how to fix this?

Best regards,


Diederik

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