Vote totals are here: http://www.fec.gov/pubrec/electionresults.shtml
Or here: http://history.house.gov/Institution/Election-Statistics/Election-Statistics/
Except for California 1976: http://www.ourcampaigns.com/RaceDetail.html?RaceID=6267
And California 1974: http://archive.org/stream/statementofvote197374cali#page/36/mode/2up/search/libertarian
LP endorsed candidates were checked against this list for 2010 - 2014: http://www.lp.org/election-results
Or, when available, against old issues of: http://ballot-access.org/print-issues/
Candidates listed on the ballot as Independents are noted with (I) or, in the 2012 Maine election, Independent For Liberty (IFL).
There are almost certainly write in candidates missing and, in the early years, possibly other LP endorsed candidates who were listed on the ballot as Independent.