Record Store Day 2015 was once again a triumph, according to merchants who participated in the event and data supplied by Nielsen Music.

For the week ended April 19 — Record Store Day was held on April 18 — the independent sector counted for 532,000 album scans, or 21.5 percent of total physical album sales, and 11.9 percent of overall sales. In both instances, it represented the highest weekly sales percentages total for the indie sector since 2003, according to Nielsen Entertainment senior VP Dave Bakula.

That total also represented a 46.7% increase over the 363,000 album units scanned by the indie sector the week prior.

Bakula also reports that for stores open more than a year, that reported both this year and last to Nielsen, same-store album sales increased 3 percent. However, overall album sales in the indie sector fell 12 percent this year versus the week of Record Store Day last year.

However, two of the most well known indie retailers, Austin Texas’ Waterloo Records and Denver’s Twist and Shout reported in each of their weekly sales e-mail that their stores enjoyed their biggest day ever this year.

“RSD 2015 was certainly one for the books,” Twist and Shout owner Paul Epstein wrote in an e-mail. “It was our most successful Record Store Day. It was our most successful day period. It was the equivalent of doing between 12-15 regular days of business (including weekends) in a 12-hour day.” Epstein continued that, compared to last year’s Record Store Day, Twist and Shout was up 35 percent.

John Kunz, owner of Austin’s well-known brick-and-mortar Waterloo Records, wrote in an e-mail to the industry that “RSD ’15 was the best sales day ever in Waterloo’s 33+ year history, eclipsing the previous high water mark by 13 percent in sales, and 9 percent in units!”

Exactly half of the weekly top 10 vinyl chart slots were occupied by Record Store Day releases, including the White Stripes’ Get Behind Me Satan, the No. 2 record; and Bob Dylan’s The Basement Tapes at No. 6. In spite of the day’s name the best selling Record Store Day release wasn’t a slab — it was Metallica’s No Life Till Leather, a cassette-only album, which sold nearly 3,000 units.

Overall for the year, the indie sector is enjoying 4.3 percent growth, with album scans so far totaling 5.6 million, versus 5.37 million last year. Bakula reckons that surging vinyl sales, which were up 53 percent in the first quarter of 2015 over the same period last year, are the prime driver for the indie sector growth.

As always with Record Store Day, there were some titles that didn’t show up on the store on time — 26 such titles at Waterloo — and records that stores expressed a wish for better allocations. Sometimes, stores just don’t, or can’t, anticipate demand for a certain title. Such was the case at Rough Trade in Brooklyn, where they didn’t anticipate that Johnny Cash’s Koncert V Praise: In Prague Live, could have been one of their best sellers, if only they ordered enough.

Nevertheless, business was booming all day at Rough Trade, which saw the line outside the door of the store reach down the corner from opening time to deep into the afternoon. [Billboard]