As discussed in slack resurface room on Apr 9, 2019:

Google phrases that as Past year/month/week;

behavior-wise pretty sure it's more common that way for such shortcuts (finding content by a rough order of recency vs. time span bound on both ends, which is easily achievable with the date selects):

The semantics of past and last is different. Taking the <P/Last> year as an example:

• Past year - any time in the last 365 days.
• Last year - anytime in 2018

Currently, the Findbar filter associates Last with any time in the last 365 days. (Similarly ... month, week):