noncontrolling interests (see Note 3 of Notes to Condensed Consolidated Financial Statements). In FY 2019 and FY 2018, financing activities also included net borrowings and repayments of $2.7 million and $10.1 million, respectively, on existing credit facilities. These financing activities on our existing credit facilities were primarily to fund our investment in the container lease fleet, make business acquisitions, pay dividends and manage our operating assets and liabilities. In FY 2019, we received proceeds of $0.6 million from issuances of common stock on the exercises of stock options.
Asset Management
Receivables and inventories were $54.8 million and $38.5 million at September 30, 2018 and $50.5 million and $22.7 million at June 30, 2018, respectively. At September 30, 2018, DSO in trade receivables were 37 days and 46 days in the Asia-Pacific area and our North American leasing operations, as compared to 35 days and 47 days at June 30, 2018, respectively. The $15.8 million increase in inventories was primarily due to the timing of receipts of sale and fleet units to fulfill known increased portable storage demand. Effective asset management is always a significant focus as we strive to apply appropriate credit and collection controls and maintain proper inventory levels to enhance cash flow and profitability.
The net book value of our total lease fleet was $437.7 million at September 30, 2018, as compared to $429.4 million at June 30, 2018. At September 30, 2018, we had 90,964 units (24,131 units in retail operations in Australia, 8,247 units in national account group operations in Australia, 12,870 units in New Zealand, which are considered retail; and 45,716 units in North America) in our lease fleet, as compared to 85,812 units (24,037 units in retail operations in Australia, 8,046 units in national account group operations in Australia, 10,222 units in New Zealand, which are considered retail; and 43,507 units in North America) at June 30, 2018. At those dates, 74,914 units (20,621 units in retail operations in Australia, 5,270 units in national account group operations in Australia, 10,932 units in New Zealand, which are considered retail; and 38,091 units in North America); and 68,712 units (20,102 units in retail operations in Australia, 5,038 units in national account group operations in Australia, 8,705 units in New Zealand, which are considered retail; and 34,867 units in North America) were on lease, respectively.
In the Asia-Pacific area, the lease fleet was comprised of 37,512 storage and freight containers and 7,736 portable building containers at September 30, 2018; and 34,507 storage and freight containers and 7,798 portable building containers at June 30, 2018. At those dates, units on lease were comprised of 31,164 storage and freight containers and 5,659 portable building containers; and 28,301 storage and freight containers and 5,544 portable building containers, respectively.
In North America, the lease fleet was comprised of 31,443 storage containers,4,427 office containers (GLOs), 4,219 portable liquid storage tank containers, 4,454 mobile offices and 1,173 modular units at September 30, 2018; and 29,518 storage containers,4,216 office containers (GLOs), 4,147 portable liquid storage tank containers, 4,447 mobile offices and 1,179 modular units at June 30, 2018. At those dates, units on lease were comprised of 25,851 storage containers, 3,866 office containers, 3,521 portable liquid storage tank containers, 3,846 mobile offices and 1,007 modular units; 23,040 storage containers, 3,620 office containers, 3,405 portable liquid storage tank containers, 3,792 mobile offices and 1,010modular units, respectively.
Contractual Obligations and Commitments
Our material contractual obligations and commitments consist of outstanding borrowings under our credit facilities discussed above and operating leases for facilities and office equipment. We believe that our contractual obligations have not changed significantly from those included in the Annual Report.
Off-Balance Sheet Arrangements
We do not maintain anyoff-balance sheet transactions, arrangements, obligations or other relationships with unconsolidated entities or others that are reasonably likely to have a material current or future effect on our financial condition, changes in financial condition, revenues or expenses, results of operations, liquidity, capital expenditures or capital resources.
Seasonality
Although demand from certain customer segments can be seasonal, our operations as a whole are not seasonal to any significant extent. We experience a reduction in sales volumes at Royal Wolf during Australia’s summer holiday break frommid-December to the end of January, followed by February being a short working day month. However, this reduction in sales typically is counterbalanced by increased levels of lease revenues derived from the removals, or moving and storage industry, which experiences its seasonal peak of personnel relocations during this same summer holiday break. Demand from some ofPac-Van’s customers can be seasonal, such as in the construction industry, which tends to increase leasing activity in the first and fourth quarters of our fiscal year; while customers in the retail industry tend to lease more units in the second quarter. Our business at Lone Star and Southern Frac, which has been significantly derived from the oil and gas industry, may decline in our second quarter months of November and December and our third quarter months of January and February, particularly if inclement weather delays, or suspends, customer projects.
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