get UNDCONTSA data from www.census.gov

Download "the total number housing under construction" from here.

1. choose "New Residential Construction"
2. "1970 from 2018"
3. choose "Housing Units under Construction"
4. "Total Units" and "United States"

Open CSV file and chop unnecessary lines at header and footer. The result must be like below.

Period,Value

Jan-1970,889

Feb-1970,888

Mar-1970,890

<.........>

Mar-2018,1124

Apr-2018,1124

When file name is "~/iCloud/R/UC-1970-2018.csv" and contains data from 1970-04-01 to 2018-04-01.

as.xts(read.csv("~/iCloud/R/UC-1970-2018.csv")[,2],seq(as.Date("1970-01-01"),as.Date("2018-04-01"),by="months"))

The below calculate data length and the date of termination accordingly.

as.xts(read.csv("~/iCloud/R/UC-1970-2018.csv")[,2],as.Date(seq(mondate(as.Date("1970-01-01")),mondate(as.Date("1970-01-01"))-1+length(read.csv("~/iCloud/R/UC-1970-2018.csv")[,2]))))

           [,1]

1970-01-01  889

1970-02-01  888

1970-03-01  890

<snipet>

2018-03-01 1124

2018-04-01 1124